Sources

Gibson R, Klima R, Van Horn J. Liquid Medication Dosing Errors: Comparison of a Ready-to-Use Vigabatrin Solution to Reconstituted Solutions of Vigabatrin Powder for Oral Solution. Adv Ther. 2025;42(3):1484-1493. PMID 39899223 · DOI 10.1007/s12325-024-03089-0 · PMC11868180 (Epub Feb 2025; often cited as 2024) PubMed · DOI

Crossover usability study with 30 lay users: 15 experienced powder caregivers and 15 syringe-naïve users. Each prepared one 1,125 mg dose of RTU surrogate solution (11.25 mL) and one of Sabril powder (22.5 mL). RTU: 30/30 within ±5%. Powder: 23/30 (77%) within ±10%. Naïve users: 13/15 within ±10%. Experienced users: 10/15 within ±10%; all experienced users were within ±3% with RTU. (Full text) Powder dose range was 425–1,390 mg (−62.2% to +23.6%). About 70% of RTU doses were within 2% of target, against 20% of powder doses. Mean % of target was 99% (95% CI 98–100) for RTU and 90% (84–96) for powder. Adjusted absolute deviation was 12 mg for RTU and 122 mg for powder. RTU was more accurate (p<0.01) and less variable (p<0.0001). COI: authors employed by Pyros (the Vigafyde NDA holder). The limitations section names single-dose design, no RTU assay, written instructions only, and low power.

Zachman M, Gong L, An L, Halvorsen MB. Dissolution and stability of vigabatrin powder in water, fruit juice, milk, and infant formula. Epilepsy Behav Rep. 2025;31:100816. PMID 40838171 · DOI 10.1016/j.ebr.2025.100816 PubMed · DOI

Vigadrone powder reconstituted in water, apple juice, whole milk or infant formula and stored at 2–8 °C in capped glass. All samples met USP 95.0–105.0% potency and impurity criteria at 0, 24 and 48 h. The Vigadrone label itself says to reconstitute in water only and discard unused solution. Authors are from Upsher-Smith/Aucta. (Cuts against a "powder is unstable" framing.)

Yin HS, Parker RM, Sanders LM, et al. Liquid Medication Errors and Dosing Tools: A Randomized Controlled Experiment. Pediatrics. 2016;138(4):e20160357. PMID 27621414 · DOI 10.1542/peds.2016-0357 PubMed · DOI

2,110 parents each measured 9 doses. 84.4% made at least one error (>20% deviation) and 21.0% made at least one large error (>2× dose). Cups were worse than syringes (aOR 4.6, 95% CI 4.2–5.1), especially for small doses. Teaspoon-only labels were worse than mL-only (aOR 1.2).

Yin HS, Parker RM, Sanders LM, et al. Pictograms, Units and Dosing Tools, and Parent Medication Errors: A Randomized Study. Pediatrics. 2017;140(1):e20163237. PMID 28759396 · DOI 10.1542/peds.2016-3237 PubMed · DOI

491 parents. 83.5% made at least one error and 29.3% made at least one large (>2×) error. Matching the syringe size to the dose volume had the biggest effect. For a 2 mL dose, a 5 mL syringe beat a 10 mL syringe (aOR 0.3). For 7.5 mL, a 10 mL syringe was best, avoiding multiple refills (5 mL vs 10 mL syringe aOR 4.0). (Relevant: larger powder volumes, such as 22.5 mL, may need several syringe-fulls.)

Yin HS, Mendelsohn AL, Wolf MS, et al. Parents' medication administration errors: role of dosing instruments and health literacy. Arch Pediatr Adolesc Med. 2010;164(2):181-186. PMID 20124148 · DOI 10.1001/archpediatrics.2009.269 PubMed · DOI

302 parents measuring a 5 mL dose. Accuracy was 30.5% with a printed cup and 50.2% with an etched cup, against >85% with oral syringes, droppers or spoons. Cup vs syringe error aOR was 26.7 (printed cup). Limited health literacy raised error risk (aOR 1.7).

Yin HS, Dreyer BP, Ugboaja DC, et al. Unit of measurement used and parent medication dosing errors. Pediatrics. 2014;134(2):e354-e361. PMID 25022742 · DOI 10.1542/peds.2014-0395 PubMed · DOI

287 ED parents. 39.4% made an error measuring the intended dose and 41.1% erred on the prescribed dose. Teaspoon/tablespoon units roughly doubled the odds of error compared with mL-only (aOR 2.3).

Yin HS, Neuspiel DR, Paul IM, et al. Preventing Home Medication Administration Errors. Pediatrics. 2021;148(6):e2021054666. PMID 34851406 · DOI 10.1542/peds.2021-054666 PubMed · DOI

AAP policy statement. Home administration errors are common, "especially when liquid preparations are used and complex medication schedules"; "children with chronic conditions are disproportionately affected." Recommends dosing-tool provision, teach-back and pictograms.

Arenas-López S, Gurung K, Tibby SM, et al. Accuracy of enteral syringes with commonly prescribed paediatric liquid medicines. Arch Dis Child. 2017;102(7):655-659. PMID 28235838 · DOI 10.1136/archdischild-2016-312492 PubMed · DOI

In vitro test of 10 drugs, volumes 0.05–5 mL, 1–5 mL syringes. Small volumes were inaccurate across all syringe sizes and brands, and 1 mL syringes were inaccurate at ≤0.1 mL. Authors suggest manufacturers revise formulation concentrations. (Double-edged for a more concentrated product; see "against" list.)

Walsh J, van Riet-Nales D, Hermans E, et al. European Paediatric Formulation Initiative workshop report: Improving the administration of oral liquid medicines in paediatrics using dosing syringes and enteral accessories. Eur J Pharm Biopharm. 2020;151:91-97. PMID 32289491 · DOI 10.1016/j.ejpb.2020.04.007 PubMed · DOI

Expert workshop: spoons and cups are unsuitable for small volumes, and syringes are better. Accuracy for very small volumes in young children "is still not sufficiently ensured."

Neves I, Auxtero MD. Dosing Accuracy of Oral Extemporaneous Suspensions of Antibiotics: Measuring Procedures and Administration Devices. Pharmaceutics. 2021;13(4):528. PMID 33920192 · DOI 10.3390/pharmaceutics13040528 PubMed · DOI

40 pharmacy students measured reconstituted azithromycin. Most ignored "shake before use". Spoons under-delivered and syringes over-delivered compared with the reference (p<0.001). This shows preparation-step errors with caregiver-reconstituted liquids. Note: azithromycin is a suspension; vigabatrin powder dissolves into a solution.

Watson C, Webb EA, Kerr S, et al. How close is the dose? Manipulation of 10 mg hydrocortisone tablets to provide appropriate doses to children. Int J Pharm. 2018;545(1-2):57-63. PMID 29705101 · DOI 10.1016/j.ijpharm.2018.04.054 PubMed · DOI

Naïve users got only 57–58% of manipulated-tablet doses within 20% of target. 74.1% of parents/carers (n=27) managed it. Conclusion: the lack of age-appropriate formulations puts children at risk of sub-optimal dosing. (Proxy evidence for splitting or crushing vigabatrin tablets; not vigabatrin-specific.)

Eserian JK, Lombardo M, Chagas JR, Galduróz JCF. Actual Versus Expected Doses of Half Tablets Containing Prescribed Psychoactive Substances: A Systematic Review. Prim Care Companion CNS Disord. 2018;20(1):17r02211. PMID 29469240 · DOI 10.4088/PCC.17r02211 PubMed · DOI

13 studies, including anticonvulsants. Splitting was satisfactory in only 55% of cases, and uneven division risks under- or overdosing.

Blackmer AB, Fox D, Arendt D, et al. Perceived Versus Demonstrated Understanding of the Complex Medications of Medically Complex Children. J Pediatr Pharmacol Ther. 2021;26(1):62-72. PMID 33424502 · DOI 10.5863/1551-6776-26.1.62 PubMed · DOI

156 medically complex children (76.9% neurologically impaired; median 8 medications). Perceived confidence was 81–99%. Only 54.8% correctly measured two doses and only 40.4% knew complete dosing parameters.

Velarde-García JF, Güeita-Rodríguez J, Jiménez-Antona C, et al. The impact of developmental and epileptic encephalopathies on families: a qualitative study. Eur J Pediatr. 2024;183(9):4103-4110. PMID 38965081 · DOI 10.1007/s00431-024-05677-2 PubMed · DOI

21 parents of children with DEEs. Themes were couple strain, impact on siblings and grandparents, and parents cutting or quitting work to provide care. (General caregiver-burden context; not IS- or formulation-specific.)

Sarpatwari A, Brown BL, McGraw SA, et al. Patient and Caregiver Experiences With and Perceptions of Risk Evaluation and Mitigation Strategy Programs With Elements to Assure Safe Use. JAMA Netw Open. 2022;5(1):e2144386. PMID 35050352 · DOI 10.1001/jamanetworkopen.2021.44386 PubMed · DOI

63 interviewees, including 10 vigabatrin patients and 4 vigabatrin caregivers. REMS reassured people but created access burdens, such as travel to certified prescribers or pharmacies, and educational materials were hard to understand.

Sarpatwari A, Brown BL, McGraw SA, et al. Physician experiences with and perceptions of risk evaluation and mitigation strategy programs with elements to assure safe use. PLoS One. 2023;18(7):e0288008. PMID 37410756 · DOI 10.1371/journal.pone.0288008 PubMed · DOI

31 physicians, 6 of them vigabatrin prescribers. Physicians understood REMS but saw limited effect on practice and raised concerns about administrative burden.

ClinicalTrials.gov NCT02220114, Orphelia Pharma. Acceptability Study of a New Paediatric Form of Vigabatrin… Completed, n=38. Source

The sponsor's registry text says Sabril granules are "not adapted for administration to infants when a fraction of the sachet is needed. Manual splitting of the sachet or lengthy and error-prone dilutions are often required." This is a sponsor statement (EU soluble-tablet developer), not a published result. No linked publication was found on PubMed. ---

Drugs@FDA (openFDA API): NDA 217684, VIGAFYDE (vigabatrin) oral solution 100 mg/mL, sponsor Pyros Pharms; original approval 2024-06-17. Source

Drugs@FDA (openFDA API): NDA 217684, VIGAFYDE (vigabatrin) oral solution 100 mg/mL, sponsor Pyros Pharms; original approval 2024-06-17.

Drugs@FDA: NDA 020427 SABRIL tablet 500 mg and NDA 022006 SABRIL for oral solution 500 mg/packet, Lundbeck. Both approved 2009-08-21. Source

Drugs@FDA: NDA 020427 SABRIL tablet 500 mg and NDA 022006 SABRIL for oral solution 500 mg/packet, Lundbeck. Both approved 2009-08-21.

Drugs@FDA (openFDA): numerous ANDAs for vigabatrin for oral solution 500 mg/packet and tablets 500 mg. Examples: VIGADRONE ANDA 210196 (approved 2018-06-21; DailyMed labeler now Upsher-Smith); VIGPODER ANDA 214961 (Pyros); Teva, Amneal, Dr. Reddy's, Zydus and others. VIGAFYDE was the only vigabatrin "SOLUTION" (ready-to-use) dosage form in the results. Source

Drugs@FDA (openFDA): numerous ANDAs for vigabatrin for oral solution 500 mg/packet and tablets 500 mg. Examples: VIGADRONE ANDA 210196 (approved 2018-06-21; DailyMed labeler now Upsher-Smith); VIGPODER ANDA 214961 (Pyros); Teva, Amneal, Dr. Reddy's, Zydus and others. VIGAFYDE was the only vigabatrin "SOLUTION" (ready-to-use) dosage form in the results.

VIGAFYDE (vigabatrin) oral solution prescribing information, revised 11/2025. Source

Indication: monotherapy for IS, 1 month to 2 years, "for whom the potential benefits outweigh the potential risk of vision loss." No rCPS indication; "not approved for use in adults." Concentration/admin: 100 mg/mL; "does not require additional reconstitution or dilution." Given orally or via G-tube; with GJ tubes, use the G-port. Flush with water after. With or without food. Use a calibrated device, not household spoons. Dosing: start 50 mg/kg/day (25 mg/kg BID). Titrate by 25–50 mg/kg/day every 3 days to a maximum of 150 mg/kg/day (75 mg/kg BID). Table 1 volumes, examples: 3 kg 0.75 mL BID start / 2.25 mL BID max; 5 kg 1.25 / 3.75 mL; 10 kg 2.5 / 7.5 mL BID. Switching (§2.3): Vigafyde needs a smaller volume than other vigabatrin products (100 vs 50 mg/mL). Verify volume when switching. How supplied/storage: 150 mL HDPE bottle (NDC 80789-003-15). Clear, peppermint-flavored, sweetened with sucralose. Inactives: methylparaben, propylparaben, peppermint flavor, purified water, sucralose. Store unopened at 20–25 °C. After opening, keep at 2–30 °C and discard 90 days after first opening. Efficacy basis (§14): "based upon a comparison of the compositional differences between vigabatrin for oral solution and VIGAFYDE". Boxed warning: permanent bilateral concentric visual field constriction; may decrease acuity. Risk rises with dose and cumulative exposure, and no dose is risk-free. Available only through the Vigabatrin REMS. Vision monitoring: baseline (no later than 4 weeks after starting), at least every 3 months on therapy, and about 3–6 months after stopping. REMS (§5.2): prescribers certified, patients enrolled, pharmacies certified. www.vigabatrinREMS.com, 1-866-244-8175. Renal: no infant dose-adjustment data. PK in adults: mild impairment AUC +30%; moderate AUC 2×; severe AUC 4.5×. Other W&P: MRI changes in infants (22% vigabatrin vs 4% other therapies, n=205); somnolence 6% vs 5% placebo and fatigue 10% vs 7% (pediatric pooled); weight gain ≥7% in 47% vs 19% (pediatric pooled); taper to stop (25–50 mg/kg every 3–4 days in the IS study).

SABRIL (vigabatrin) for oral solution prescribing information, revised 10/2021. Source

Indications: rCPS adjunct from age 2 (not first-line); IS monotherapy 1 month–2 years. Reconstitution (§2.5): "Empty the entire contents of each 500 mg packet into a clean cup, and dissolve in 10 mL of cold or room temperature water per packet." Final concentration 50 mg/mL. Table 3: dose 0–500 mg = 1 packet + 10 mL; 501–1000 mg = 2 packets + 20 mL; 1001–1500 mg = 3 packets + 30 mL. "Discard the resulting solution if it is not clear… Each individual dose should be prepared and used immediately. Discard any unused portion." 3 mL or 10 mL oral syringes are supplied separately by the pharmacy. IS volumes (Table 2, 50 mg/mL): 3 kg 1.5 mL BID start / 4.5 mL max; 10 kg 5 / 15 mL; 16 kg 8 / 24 mL BID. Counseling (§17): "Physicians should confirm that caregivers(s) understand how to mix SABRIL for oral solution and to administer the correct dose." Storage: 20–25 °C; packages of 50 packets. (Derived from the label, not a study: a 5 kg infant starting at 125 mg BID uses one 500 mg packet per dose and discards 7.5 mL, i.e. 375 mg, twice daily.)

SABRIL (vigabatrin) tablets prescribing information, revised 10/2021. Source

500 mg film-coated tablet, scored, bottles of 100. rCPS adults (≥17): start 1,000 mg/day (500 mg BID), increase by 500 mg weekly, recommended 3,000 mg/day. 6,000 mg/day adds no benefit and more adverse events. rCPS pediatrics (2–16 y), Table 1, total daily dose start → maintenance: 10–15 kg 350 → 1,050 mg; >15–20 kg 450 → 1,300 mg; >20–25 kg 500 → 1,500 mg; >25–60 kg 500 → 2,000 mg; >60 kg dosed as adults. Withdraw if no substantial benefit within 3 months (rCPS) or 2–4 weeks (IS). Renal (≥2 y and adults): CLcr >50–80 reduce dose 25%; >30–50 reduce 50%; >10–30 reduce 75%. No infant data. "Bioequivalence has been established between the oral solution and tablet formulations." Vision: "Based upon adult studies, 30 percent or more of patients can be affected"; severe cases can mean tunnel vision within 10°. rCPS trials: Study 1 (n=174) ≥50% responders 51% at 3 g/day and 53% at 6 g/day vs 9% placebo. PK: half-life 5.7 h (infants), 6.8 h (3–9 y), 9.5 h (10–16 y), 10.5 h (adults). About 95% of radiolabel recovered in urine, 80% of it parent drug. Tmax about 1 h (children/adults) and 2.5 h (infants).

VIGADRONE (vigabatrin) for oral solution, revised 12/2025, Upsher-Smith. Source

Same reconstitution as Sabril: 10 mL water per 500 mg packet, 50 mg/mL, prepare each dose immediately, discard any unused portion. Cartons of 50 packets.

Vigabatrin REMS: www.vigabatrinREMS.com (as cited in both labels). Requirements as summarized under label-vigafyde-2025 §5.2. (The REMS website itself was not fetched; requirements are cited from the FDA labels.) Source

Vigabatrin REMS: www.vigabatrinREMS.com (as cited in both labels). Requirements as summarized under label-vigafyde-2025 §5.2. (The REMS website itself was not fetched; requirements are cited from the FDA labels.)

NIOSH. NIOSH List of Hazardous Drugs in Healthcare Settings, 2024. Ovesen JL, Sammons D, Connor TH, et al. DHHS (NIOSH) Publication No. 2025-103, December 2024 (supersedes 2016-161). DOI 10.26616/NIOSHPUB2025103 · DOI

Vigabatrin: Table 2, AHFS 28:12.92 (anticonvulsants, miscellaneous), not a biologic, "Only Developmental and/or Reproductive Hazard" = Yes. Change log: "Moved from Table 3 to Table 2". In the 2016 list, Table 3 held non-antineoplastic drugs with only reproductive or developmental hazard; the 2024 list merged these into Table 2 with a flag. Table 2 definition: drugs that meet the NIOSH hazardous-drug definition, have no manufacturer's special handling information (MSHI), and are not NTP "known human carcinogen" or IARC Group 1/2A.

NIOSH. Managing Hazardous Drug Exposures: Information for Healthcare Settings. Hodson L, Ovesen J, Couch J, et al. DHHS (NIOSH) Publication No. 2023-130, April 2023. DOI 10.26616/NIOSHPUB2023130 DOI

"Crushing tablets or opening capsules should be avoided, and liquid formulations should be used whenever possible." "Cutting, crushing, or otherwise manipulating tablets and capsules will increase the potential for exposure of workers." Table of Control Approaches (healthcare workers): Administering intact tablets: single gloves. Crushing or manipulating tablets: ventilated engineering control, double chemo gloves, gown, and N95 if done outside the control; consider a pill pouch. Administering an oral liquid by mouth or feeding tube: double gloves and gown; eye protection if splash is likely. Even reproductive-only drugs warrant facility risk management for all staff, not only those who are pregnant.

USP. USP <800> FAQs, updated January 21, 2026. Source

<800> became official 1 Dec 2019 and compendially applicable (as far as <795>/<797> apply) on 1 Nov 2023. For HDs other than active pharmaceutical ingredients (APIs) and NIOSH Table 1 antineoplastics, facilities may do an assessment of risk by drug and dosage form. "Crushing HD tablets or opening capsules may have more risk of exposure than dispensing tablets without further manipulation." Example mitigations include unit-dose packaging and reassigning pregnant staff. <800> covers healthcare personnel and settings, not home caregivers. Relevance to vigabatrin: pharmacy or clinic staff who crush tablets or prepare doses should follow a vigabatrin-specific assessment of risk. ---

Elterman RD, Shields WD, Mansfield KA, Nakagawa J; US Infantile Spasms Vigabatrin Study Group. Randomized trial of vigabatrin in patients with infantile spasms. Neurology. 2001;57(8):1416-1421. PMID 11673582 · DOI 10.1212/wnl.57.8.1416 PubMed · DOI

Low dose (18–36 mg/kg/day) vs high dose (100–148 mg/kg/day). Responders: 8/75 on low dose vs 24/67 on high dose (p<0.001). Faster response with TSC (p<0.001). 9 discontinued for adverse events.

Elterman RD, Shields WD, Bittman RM, et al. Vigabatrin for the treatment of infantile spasms: final report of a randomized trial. J Child Neurol. 2010;25(11):1340-1347. PMID 20404353 · DOI 10.1177/0883073810365103 PubMed · DOI

Modified ITT n=221. Video-EEG-confirmed spasm cessation: 15.9% (17/107) high dose vs 7.0% (8/114) low dose (p=0.0375). 23% relapsed during follow-up, and 72% of those regained spasm freedom. This is the label's IS "Study 1".

Lux AL, Edwards SW, Hancock E, et al. The United Kingdom Infantile Spasms Study comparing vigabatrin with prednisolone or tetracosactide at 14 days: a multicentre, randomised controlled trial. Lancet. 2004;364(9447):1773-1778. PMID 15541450 · DOI 10.1016/S0140-6736(04)17400-X17400-X) PubMed · DOI

n=107 (TSC excluded). No spasms on days 13–14: hormonal 73% (40/55) vs vigabatrin 54% (28/52); difference 19% (p=0.043). Adverse events 55% vs 54%.

Lux AL, Edwards SW, Hancock E, et al. The United Kingdom Infantile Spasms Study (UKISS) comparing hormone treatment with vigabatrin on developmental and epilepsy outcomes to age 14 months: a multicentre randomised trial. Lancet Neurol. 2005;4(11):712-717. PMID 16239177 · DOI 10.1016/S1474-4422(05)70199-X70199-X) PubMed · DOI

Spasm-free at 12–14 months: hormone 75% vs vigabatrin 76% (p=0.82). Vineland Adaptive Behavior Scales (VABS) score was similar overall. With no identified cause, VABS was 88.2 (hormone) vs 78.9 (vigabatrin), p=0.025.

Darke K, Edwards SW, Hancock E, et al. Developmental and epilepsy outcomes at age 4 years in the UKISS trial comparing hormonal treatments to vigabatrin for infantile spasms: a multi-centre randomised trial. Arch Dis Child. 2010;95(5):382-386. PMID 20457702 · DOI 10.1136/adc.2009.160606 PubMed · DOI

77 traced. Overall VABS was not significantly different (median 60 vs 50; p=0.091). No identified cause: 96 vs 63 (p=0.033) favoring hormones.

O'Callaghan FJ, Lux AL, Darke K, et al. The effect of lead time to treatment and of age of onset on developmental outcome at 4 years in infantile spasms: evidence from the United Kingdom Infantile Spasms Study. Epilepsia. 2011;52(7):1359-1364. PMID 21668442 · DOI 10.1111/j.1528-1167.2011.03127.x PubMed · DOI

Each step up in lead-time category was linked to a 3.9-point lower VABS score at 4 years (p=0.014).

O'Callaghan FJ, Edwards SW, Alber FD, et al. Safety and effectiveness of hormonal treatment versus hormonal treatment with vigabatrin for infantile spasms (ICISS): a randomised, multicentre, open-label trial. Lancet Neurol. 2017;16(1):33-42. PMID 27838190 · DOI 10.1016/S1474-4422(16)30294-030294-0) PubMed · DOI

n=377. No spasms days 14–42: combination 72% (133/186) vs hormone alone 57% (108/191); difference 15.0% (95% CI 5.1–24.9; p=0.002). Vigabatrin minimum 100 mg/kg/day.

O'Callaghan FJK, Edwards SW, Alber FD, et al. Vigabatrin with hormonal treatment versus hormonal treatment alone (ICISS) for infantile spasms: 18-month outcomes of an open-label, randomised controlled trial. Lancet Child Adolesc Health. 2018;2(10):715-725. PMID 30236380 · DOI 10.1016/S2352-4642(18)30244-X30244-X) PubMed · DOI

VABS at 18 months was no different (73.9 vs 72.7; p=0.55), and epilepsy rates were similar (30.0% vs 29.2%). Early spasm control was linked to VABS 79.1 vs 63.2 (p<0.001). Longer lead time was linked to lower VABS (p<0.001).

Hancock EC, Osborne JP, Edwards SW. Treatment of infantile spasms. Cochrane Database Syst Rev. 2013;(6):CD001770. PMID 23740534 · DOI 10.1002/14651858.CD001770.pub3 PubMed · DOI

18 RCTs, 916 patients, mostly poor methodology. Hormones resolve spasms faster and in more infants than vigabatrin. "If prednisolone or vigabatrin is used, high dosage is recommended. Vigabatrin may be the treatment of choice in tuberous sclerosis."

Xu Z, Gong P, Jiao X, et al. Efficacy of vigabatrin in the treatment of infantile epileptic spasms syndrome: A systematic review and meta-analysis. Epilepsia Open. 2023;8(2):268-277. PMID 36740237 · DOI 10.1002/epi4.12703 PubMed · DOI

5 RCTs: vigabatrin monotherapy was inferior to hormonal monotherapy (OR 0.37, 95% CI 0.20–0.67). Observational studies agree (OR 0.61). Vigabatrin works better in TSC than other causes (OR 5.59, 95% CI 2.17–14.41). Combination vs hormone: OR 0.75 (95% CI 0.09–6.45, not significant).

Knupp KG, Coryell J, Nickels KC, et al. Response to treatment in a prospective national infantile spasms cohort. Ann Neurol. 2016;79(3):475-484. PMID 26704170 · DOI 10.1002/ana.24594 PubMed · DOI

230 infants, 22 US centers. Sustained 3-month response: ACTH 55%, oral steroids 39%, vigabatrin 36%, non-standard 9% (p<0.001).

Yuskaitis CJ, Mytinger JR, Baumer FM, et al. Association of Time to Clinical Remission With Sustained Resolution in Children With New-Onset Infantile Spasms. Neurology. 2022;99(22):e2494-e2503. PMID 36038267 · DOI 10.1212/WNL.0000000000201232 PubMed · DOI

395 infants. 43% remitted within 2 weeks, and 81% of those within week 1. Median time to response: vigabatrin 3 days (IQR 1–6), ACTH 4, steroids 3. Non-responders at 1 week should be reassessed immediately. (Supports accurate dosing during the critical first-week titration.)

Mytinger JR, Albert DVF, Twanow JD, et al. Compliance With Standard Therapies and Remission Rates After Implementation of an Infantile Spasms Management Guideline. Pediatr Neurol. 2020;104:23-29. PMID 31911027 · DOI 10.1016/j.pediatrneurol.2019.11.016 PubMed · DOI

115 patients. Initial and 3-month remission: ACTH 66%/79%, prednisolone 53%/83%, vigabatrin 19%/40%. Here "compliance" means clinician guideline adherence, not caregiver adherence.

Chiron C, Dumas C, Jambaqué I, et al. Randomized trial comparing vigabatrin and hydrocortisone in infantile spasms due to tuberous sclerosis. Epilepsy Res. 1997;26(2):389-395. PMID 9095401 · DOI 10.1016/s0920-1211(96)01006-601006-6) PubMed · DOI

n=22. Spasm-free: vigabatrin (150 mg/kg/day) 11/11 vs hydrocortisone 5/11 (p<0.01). Mean time to cessation 3.5 vs 13 days. All 7 crossed over to vigabatrin were controlled.

Hancock E, Osborne JP. Vigabatrin in the treatment of infantile spasms in tuberous sclerosis: literature review. J Child Neurol. 1999;14(2):71-74. PMID 10073425 · DOI 10.1177/088307389901400201 PubMed · DOI

Complete cessation in 73/77 (95%) with TSC vs 170/313 (54%) without.

Prezioso G, Chiarelli F, Matricardi S, et al. Efficacy and safety of vigabatrin in patients with tuberous sclerosis complex and infantile epileptic spasm syndrome: a systematic review. Expert Rev Neurother. 2023;23(7):661-671. PMID 37243682 · DOI 10.1080/14737175.2023.2216385 PubMed · DOI

17 studies. Overall response 67% (231/343). Spasm-free rate in RCTs 88% (29/33). Evidence is low level and heterogeneous.

Northrup H, Aronow ME, Bebin EM, et al. Updated International Tuberous Sclerosis Complex Diagnostic Criteria and Surveillance and Management Recommendations. Pediatr Neurol. 2021;123:50-66. PMID 34399110 · DOI 10.1016/j.pediatrneurol.2021.07.011 PubMed · DOI

2018 consensus update. Abstract: increased emphasis on early EEG screening for epileptiform abnormalities. (Full text was not accessible to us, so the vigabatrin-specific recommendation wording is unverified. Pull the exact sentence before quoting.)

Kotulska K, Kwiatkowski DJ, Curatolo P, et al. Prevention of Epilepsy in Infants with Tuberous Sclerosis Complex in the EPISTOP Trial. Ann Neurol. 2021;89(2):304-314. PMID 33180985 · DOI 10.1002/ana.25956 · NCT02098759 PubMed · DOI

94 infants. Time to first seizure was longer with preventive than conventional vigabatrin: 364 vs 124 days in the RCT, 426 vs 106 days in the open-label trial. At 24 months, preventive treatment lowered the risk of clinical seizures (OR 0.21), DRE (OR 0.23) and IS (OR 0, p<0.001).

Bebin EM, Peters JM, Porter BE, et al. Early Treatment with Vigabatrin Does Not Decrease Focal Seizures or Improve Cognition in Tuberous Sclerosis Complex: The PREVeNT Trial. Ann Neurol. 2023 (Epub 2023 Aug 28; PubMed record lists no volume/pages yet). PMID 37638552 · DOI 10.1002/ana.26778 · NCT02849457 PubMed · DOI

56 randomized (29 vigabatrin, 27 placebo). Bayley-III cognition at 24 months was similar. No difference in epilepsy incidence or DRE. IS incidence was lower and later with vigabatrin.

Dean C, Mosier M, Penry K. Dose-Response Study of Vigabatrin as add-on therapy in patients with uncontrolled complex partial seizures. Epilepsia. 1999;40(1):74-82. PMID 9924905 · DOI 10.1111/j.1528-1157.1999.tb01991.x PubMed · DOI

n=174. ≥50% responders: placebo 7%; 1 g 24%; 3 g 51%; 6 g 54%. 6 g had more dropouts.

Bresnahan R, Gianatsi M, Maguire MJ, et al. Vigabatrin add-on therapy for drug-resistant focal epilepsy. Cochrane Database Syst Rev. 2020;7(7):CD007302. PMID 32730657 · DOI 10.1002/14651858.CD007302.pub3 PubMed · DOI

11 trials, 756 participants aged 10–64. ≥50% response RR 2.60 (95% CI 1.87–3.63), low certainty. Withdrawal RR 2.86. More dizziness (RR 1.74), fatigue (1.65), drowsiness (1.70) and depression (3.28). Results "should not be extrapolated to children under 10."

Chadwick D. Safety and efficacy of vigabatrin and carbamazepine in newly diagnosed epilepsy: a multicentre randomised double-blind study. Lancet. 1999;354(9172):13-19. PMID 10406359 · DOI 10.1016/s0140-6736(98)10531-710531-7) PubMed · DOI

n=459. Vigabatrin was less effective (time to first seizure p=0.0001) but better tolerated. Weight gain 11% vs 5%; psychiatric symptoms 25% vs 15%. Not recommended first-line. ---

Maguire MJ, Hemming K, Wild JM, et al. Prevalence of visual field loss following exposure to vigabatrin therapy: a systematic review. Epilepsia. 2010;51(12):2423-2431. PMID 21070215 · DOI 10.1111/j.1528-1167.2010.02772.x PubMed · DOI

32 studies; 1,678 exposed and 406 controls. Field loss in 44% exposed vs 7% controls. Pooled: adults 52% (95% CI 46–59), children 34% (25–42). RR 4.0 (2.9–5.5). Risk rose with cumulative dose and age.

Riikonen R, Rener-Primec Z, Carmant L, et al. Does vigabatrin treatment for infantile spasms cause visual field defects? An international multicentre study. Dev Med Child Neurol. 2015;57(1):60-67. PMID 25145415 · DOI 10.1111/dmcn.12573 PubMed · DOI

School-age follow-up: visual field defects (VFDs) in 11/32 (34%). By duration: <1 y 9%, 12–24 mo 30%, >2 y 63%. TSC 6/10.

Gaily E, Jonsson H, Lappi M. Visual fields at school-age in children treated with vigabatrin in infancy. Epilepsia. 2009;50(2):206-216. PMID 19215279 · DOI 10.1111/j.1528-1167.2008.01961.x PubMed · DOI

16 children treated in infancy (mean 21 months). Only 1 (6%) had mild loss. Risk may be lower with exposure in infancy.

Schwarz MD, Li M, Tsao J, et al. A lack of clinically apparent vision loss among patients treated with vigabatrin with infantile spasms: The UCLA experience. Epilepsy Behav. 2016;57(Pt A):29-33. PMID 26921595 · DOI 10.1016/j.yebeh.2016.01.012 PubMed · DOI

143 treated. No clinically apparent vigabatrin-attributable vision loss (upper 95% bound 3.2%). Median exposure 8.6 months; median peak dose 141.5 mg/kg/day. Visual loss from any cause was 31% with vigabatrin vs 32% without.

Wild JM, Fone DL, Aljarudi S, et al. Modelling the risk of visual field loss arising from long-term exposure to the antiepileptic drug vigabatrin: a cross-sectional approach. CNS Drugs. 2013;27(10):841-849. PMID 23990316 · DOI 10.1007/s40263-013-0100-z PubMed · DOI

147 adults with rCPS, median exposure 7.9 years. 59% had vigabatrin-associated visual field loss (VAVFL). Modelled frequency plateaued at about 76% after about 6 years or about 79% after 5 kg cumulative dose.

Conway M, Cubbidge RP, Hosking SL. Visual field severity indices demonstrate dose-dependent visual loss from vigabatrin therapy. Epilepsia. 2008;49(1):108-116. PMID 18184224 · DOI 10.1111/j.1528-1167.2007.01249.x PubMed · DOI

n=31 adults. Maximum daily dose, not cumulative dose or duration, was the only significant predictor of defect severity (p=0.012–0.020). (Indirect argument that unintended overdoses matter; speculative, do not overstate.)

Buncic JR, Westall CA, Panton CM, et al. Characteristic retinal atrophy with secondary "inverse" optic atrophy identifies vigabatrin toxicity in children. Ophthalmology. 2004;111(10):1935-1942. PMID 15465561 · DOI 10.1016/j.ophtha.2004.03.036 PubMed · DOI

138 mostly infants with electroretinogram (ERG) every 6 months. 3 had definite peripheral retinal nerve-fiber-layer atrophy with "inverse" nasal optic atrophy.

Durbin S, Mirabella G, Buncic JR, et al. Reduced grating acuity associated with retinal toxicity in children with infantile spasms on vigabatrin therapy. Invest Ophthalmol Vis Sci. 2009;50(8):4011-4016. PMID 19279311 · DOI 10.1167/iovs.08-3237 PubMed · DOI

42 children with IS. Grating acuity (sweep VEP) was reduced in those with ERG-defined retinal toxicity.

Sergott RC, Westall CA. Primer on visual field testing, electroretinography, and other visual assessments for patients treated with vigabatrin. Acta Neurol Scand Suppl. 2011;(192):48-56. PMID 22061180 · DOI 10.1111/j.1600-0404.2011.01600.x PubMed · DOI

REMS designed around baseline exam within 4 weeks plus ongoing monitoring. Reviews perimetry, ERG and other methods for adults and infants.

Plant GT, Sergott RC. Understanding and interpreting vision safety issues with vigabatrin therapy. Acta Neurol Scand Suppl. 2011;(192):57-71. PMID 22061181 · DOI 10.1111/j.1600-0404.2011.01601.x PubMed · DOI

Bilateral field constriction also occurs, less often, in vigabatrin-naïve patients with epilepsy. Reviews the taurine-deficiency hypothesis.

Pearl PL, Vezina LG, Saneto RP, et al. Cerebral MRI abnormalities associated with vigabatrin therapy. Epilepsia. 2009;50(2):184-194. PMID 18783433 · DOI 10.1111/j.1528-1167.2008.01728.x PubMed · DOI

New, reversible T2/DWI changes in 7/22 (32%) on vigabatrin, all treated for IS. Affected patients were younger (median 11 months) and on higher doses (170 vs 87 mg/kg/day). None of 56 unexposed IS patients had them.

Wheless JW, Carmant L, Bebin M, et al. Magnetic resonance imaging abnormalities associated with vigabatrin in patients with epilepsy. Epilepsia. 2009;50(2):195-205. PMID 19054414 · DOI 10.1111/j.1528-1167.2008.01896.x PubMed · DOI

205 infants with IS: MRI abnormalities in 22% with vigabatrin vs 4% without (p<0.001). Resolved in 6/9 with follow-up. No excess in children or adults with rCPS. (Source of the label's 22% vs 4%.)

Dracopoulos A, Widjaja E, Raybaud C, et al. Vigabatrin-associated reversible MRI signal changes in patients with infantile spasms. Epilepsia. 2010;51(7):1297-1304. PMID 20384718 · DOI 10.1111/j.1528-1167.2010.02564.x PubMed · DOI

25/81 (30.9%) had abnormal signal on vigabatrin ≥120 mg/kg/day, reversible on withdrawal. Higher risk at ≤12 months of age.

Hussain SA, Tsao J, Li M, et al. Risk of vigabatrin-associated brain abnormalities on MRI in the treatment of infantile spasms is dose-dependent. Epilepsia. 2017;58(4):674-682. PMID 28230253 · DOI 10.1111/epi.13712 PubMed · DOI

Asymptomatic vigabatrin-associated MRI changes (VABAM) were linked to peak dose (p=0.0028), not cumulative dose; 6/40 asymptomatic scans. Symptomatic VABAM in 4/104, possibly linked to concurrent hormones (p=0.039). Caution above 175 mg/kg/day. (Peak-dose dependence is one reason to avoid accidental overdoses.)

Sathe R, Shrestha G, Terango A, et al. Symptomatic vigabatrin-associated MRI toxicity is associated with simultaneous hormonal therapy among patients with infantile spasms. Epilepsia Open. 2025;10(1):314-320. PMID 39570186 · DOI 10.1002/epi4.13099 PubMed · DOI

VABAM in 17/108 (11 symptomatic). Symptomatic VABAM was linked to concurrent hormones (p=0.001) and not to peak dose. (Partly conflicts with Hussain 2017 on dose dependence.)

Walker SD, Kälviäinen R. Non-vision adverse events with vigabatrin therapy. Acta Neurol Scand Suppl. 2011;(192):72-82. PMID 22061182 · DOI 10.1111/j.1600-0404.2011.01602.x PubMed · DOI

Common in infants: sedation, somnolence, irritability. In adults: drowsiness, dizziness, headache, fatigue. Depression and psychosis were more frequent than with placebo. Reviews the intramyelinic edema history. (See also label-vigafyde-2025 for somnolence, fatigue, weight gain and MRI figures, and lancet-1999-chadwick-vs-cbz for weight gain of 11% vs 5%.) ---

Rey E, Pons G, Olive G. Vigabatrin. Clinical pharmacokinetics. Clin Pharmacokinet. 1992;23(4):267-278. PMID 1395360 · DOI 10.2165/00003088-199223040-00003 PubMed · DOI

Racemic drug; the S(+) enantiomer is active, with no chiral inversion. Peak at 1–2 h, linear PK, no protein binding, Vd about 0.8 L/kg. Half-life 5.3–7.4 h (S+ 7.5 h). About 70% excreted renally. "The action of the drug long outlasts its presence in plasma." Reduce dose in renal impairment.

Schechter PJ. Clinical pharmacology of vigabatrin. Br J Clin Pharmacol. 1989;27(Suppl 1):19S-22S. PMID 2667604 · DOI 10.1111/j.1365-2125.1989.tb03456.x PubMed · DOI

Half-life 5–7 h. About 65% excreted unchanged in urine within 24 h. Dose-related rises in CSF GABA, consistent with GABA-transaminase (GABA-T) inhibition.

Gidal BE, Privitera MD, Sheth RD, et al. Vigabatrin: a novel therapy for seizure disorders. Ann Pharmacother. 1999;33(12):1277-1286. PMID 10630829 · DOI 10.1345/aph.18376 PubMed · DOI

Selective, irreversible GABA-T inhibitor. No clinically significant interactions and no need for level monitoring.

Nielsen JC, Kowalski KG, Karim A, et al. Population pharmacokinetics analysis of vigabatrin in adults and children with epilepsy and children with infantile spasms. Clin Pharmacokinet. 2014;53(11):1019-1031. PMID 25172554 · DOI 10.1007/s40262-014-0172-z PubMed · DOI

349 adults and 119 pediatric patients. Clearance rises with creatinine clearance. Absorption is slower in younger patients. In infants with IS, inter-occasion variability in relative bioavailability was 26.9%.

Jacqz-Aigrain E, Guillonneau M, Rey E, et al. Pharmacokinetics of the S(+) and R(-) enantiomers of vigabatrin during chronic dosing in a patient with renal failure. Br J Clin Pharmacol. 1997;44(2):183-185. PMID 9278207 · DOI 10.1046/j.1365-2125.1997.00636.x PubMed · DOI

Case of TSC with renal failure and agitation on 3 g/day. Stereoselective accumulation of R(−). Hemodialysis clearance was about 5 L/h for both enantiomers. (Label PK, from label-sabril-tablet-2021 and label-vigafyde-2025: essentially complete absorption; infant Tmax about 2.5 h; infant t½ 5.7 h; infant CL 2.4 L/h; food lowers Cmax 33% with unchanged AUC; induces CYP2C9; lowers phenytoin 16–20%.) ---

Go CY, Mackay MT, Weiss SK, et al. Evidence-based guideline update: medical treatment of infantile spasms. Report of the Guideline Development Subcommittee of the American Academy of Neurology and the Practice Committee of the Child Neurology Society. Neurology. 2012;78(24):1974-1980. PMID 22689735 · DOI 10.1212/WNL.0b013e318259e2cf PubMed · DOI

PubMed now marks this guideline "[RETIRED]." Cite it as historical. Findings: ACTH more effective than vigabatrin short-term (excluding TSC); ACTH or vigabatrin "may be useful", with ACTH preferred; hormones preferred for cryptogenic IS for development; shorter lag to treatment possibly improves outcomes.

Pellock JM, Hrachovy R, Shinnar S, et al. Infantile spasms: a U.S. consensus report. Epilepsia. 2010;51(10):2175-2189. PMID 20608959 · DOI 10.1111/j.1528-1167.2010.02657.x PubMed · DOI

Consensus: early recognition, short-duration first-line therapy, timely EEG to judge response, prompt treatment changes.

Wilmshurst JM, Gaillard WD, Vinayan KP, et al. Summary of recommendations for the management of infantile seizures: Task Force Report for the ILAE Commission of Pediatrics. Epilepsia. 2015;56(8):1185-1197. PMID 26122601 · DOI 10.1111/epi.13057 PubMed · DOI

ACTH preferred for short-term spasm control (level B), oral steroids probably effective (level C), and shorter time to treatment may improve outcome (level C).

Erdemir G, Rao CK, Pino AF, et al. Diagnosis and management guidelines for infantile epileptic spasms syndrome around the world: A scoping review and comparative study of international approaches. Epilepsia. 2026;67(9):4600-4617. PMID 42274306 · DOI 10.1002/epi.70329 PubMed · DOI

28 guidelines (16 published, 12 unpublished). Vigabatrin was universally recommended as first-line for TSC-associated IESS. Recent guidelines (2016–2024) increasingly endorse prednisolone and vigabatrin; combination therapy appears in about 25% after 2017. Response is usually assessed at about 14 days.

Freedman D, Babatunde I, Morgan RL, et al. American Epilepsy Society Clinical Practice Guideline: Infantile Epilepsy. Epilepsy Curr. 2026;26(3):174-202. PMID 41969626 · DOI 10.1177/15357597261433266 PubMed · DOI

Covers epilepsy from 1 to <36 months. Explicitly excludes West syndrome and IS ("existing treatment guidance is already available"). Useful only to show there is no newer US IS-specific guideline in this document.

Treadwell JR, Kessler SK, Wu M, et al. Pharmacologic and Dietary Treatments for Epilepsies in Children Aged 1-36 Months: A Systematic Review. Neurology. 2023;100(1):e16-e27. PMID 36270899 · DOI 10.1212/WNL.0000000000201026 PubMed · DOI

The evidence base for the AES guideline (excludes IS). Vigabatrin data were insufficient for conclusions in non-IS infant epilepsy.

Ramantani G, Bölsterli BK, Alber M, et al. Treatment of Infantile Spasm Syndrome: Update from the Interdisciplinary Guideline Committee Coordinated by the German-Speaking Society of Neuropediatrics. Neuropediatrics. 2022;53(6):389-401. PMID 35882373 · DOI 10.1055/a-1909-2977 PubMed · DOI

(Identity verified via esummary only; abstract not reviewed. Read before citing specifics.) ---