Prescribing guide
Diacomit (stiripentol)Weight-based dosing, blood count schedule, clobazam interaction and prior authorization criteria for Dravet syndromeFor prescribers and their offices treating Dravet syndrome: what the pharmacy needs before it ships, what the prior authorization wants documented, the titration and the monitoring the label requires.
Dispensing gate
No REMS and no contraindications on the label: baseline blood counts, concomitant clobazam, then prior authorization and a prescription routed to PANTHERx Rare Pharmacy, the exclusive dispenser.
Example PA threshold
Cigna example: age 6 months or older and 7kg or more, taking clobazam or unable to because of adverse events, prescribed by or in consultation with a neurologist, 1-year approval.
Monitoring
Hematologic testing at baseline and every 6 months; weight in all patients and growth rate in children; somnolence, especially with clobazam and other CNS depressants; mood and suicidality.
Support line
Biocodex By Your Side Support Team at PANTHERx: 833-248-0467, weekdays 8 AM to 8 PM ET; $0 copay for eligible commercial plans; Quick Start and Bridge supplies of up to 60 days; Long-Term Patient Assistance Program.
Give your patient their plan
A one-page handout for starting Diacomit, in plain language: what the first fill waits on, the first dates, who will call and the symptoms to report, with blank lines for the start date and your office's number. The link opens the patient's full first 90 days page, where their dates become calendar entries.
trialfriend.com/p/diacomitBefore the first fill: REMS, labs and enrollment
The steps that the pharmacy, the REMS or the drugmaker's program will wait on, in the order they usually need to happen. A first fill of a specialty drug most often stalls on one of these rather than on the plan.
| Step | What it requires | Source |
|---|---|---|
| Baseline labs | Obtain hematologic testing before starting Diacomit (sections 2.1 and 5.3). | FDA label |
| Confirm clobazam | The indication is for patients taking clobazam who are 6 months or older and weigh 7kg or more; the label states there are no clinical data to support monotherapy. | FDA label |
| Choose the formulation | Capsules or powder for oral suspension, each 250mg or 500mg; strengths can be combined. The powder contains phenylalanine, so consider total daily intake from all sources in PKU. | FDA label |
| Route to PANTHERx | Fax the completed Patient Enrollment Form to PANTHERx at 833-871-4137, or send an e-prescription to PANTHERx through the EHR. Biocodex states Diacomit is available exclusively through PANTHERx Rare Pharmacy. | Access, HCP page |
| What to include | Diagnosis code(s) and weight; formulation, dosing instructions and quantity; prescription and medical benefit cards if using the form; current, discontinued or failed medications including clobazam use and dose; medical records; an office contact name and phone number. | Access, HCP page |
| Authorization delays | The enrollment form has a Quick Start section for prior authorization delays, subject to patient eligibility criteria; Biocodex describes Quick Start as up to 60 days at no cost for newly eligible patients. | Enrollment form |
| Pharmacy follow-up | The support team helps with prior authorization, reauthorization and appeals, runs benefit investigations, and contacts the office for additional refills once the final prescription has been filled. | Access, HCP page |
Prior authorization criteria and what to document
One public policy as the example: Cigna, May 1, 2026. Approval approved a year at a time. Renewal needs the patient to be responding, such as reduced seizure severity, frequency or duration, as judged by the prescriber. This version took effect May 1, 2026 and cites the July 2022 label. The April 2026 label revision added pneumonia to side effects reported since approval and did not change the indication or dosing. The label itself covers only patients who are taking clobazam with Diacomit. Other health plans set their own criteria and their own approval lengths. It is here as an example of what a plan asks for, not as a rule.
| Element | What the policy asks | In the chart | Source |
|---|---|---|---|
| Age and weight | 6 months of age or older and weighing 7kg or more | Date of birth and a current weight on the request | Cigna policy |
| Diagnosis | Seizures associated with Dravet syndrome | Neurology note with the diagnosis | Cigna policy |
| Clobazam | Taking concomitant clobazam, or unable to take clobazam due to adverse events as determined by the prescriber | Current medication list with the clobazam dose, or the note documenting the adverse events | Cigna policy |
| Prescriber | Prescribed by or in consultation with a neurologist | Specialty on the request, or the consult note | Cigna policy |
| Continuation | Responding to therapy, such as reduced seizure severity, frequency or duration, as determined by the prescriber; approval 1 year | Seizure diary or progress note | Cigna policy |
Diacomit dosing and titration
| When | Label | Source |
|---|---|---|
| 6 months to under 1 year, 7kg and above | 25mg/kg twice daily (50mg/kg/day). Not more than twice daily, to limit free water administration and avoid overexposure. | FDA label |
| 1 year and above, 7kg to under 10kg | 25mg/kg twice daily (50mg/kg/day). Not more than twice daily, to avoid overexposure. | FDA label |
| 1 year and above, 10kg and above | 25mg/kg twice daily or 16.67mg/kg three times daily (50mg/kg/day). | FDA label |
| Maximum and rounding | Maximum 3,000mg a day. If the exact dose is not achievable, round to the nearest possible dose, usually within 50mg to 150mg of 50mg/kg/day; the two strengths can be combined. | FDA label |
| Titration | The label gives no titration schedule; the pivotal trials used a fixed 50mg/kg/day in divided doses with no dose titration. | FDA label |
| Administration | Capsules: swallow whole with a glass of water during a meal; do not break or open. Powder: mix in 100mL of water, take immediately during a meal, then add 25mL of water to the cup and drink it. | FDA label |
| Missed dose | Take as soon as possible; if almost time for the next dose, skip it and take the next scheduled dose. Do not double doses. | FDA label |
| Supply | 250mg and 500mg capsules in bottles of 60; 250mg and 500mg packets in cartons of 60. Store dry at 20 to 25°C in the original package, protected from light. | FDA label |
| Renal and hepatic impairment | No formal pharmacokinetic studies; not recommended in moderate or severe renal impairment or in moderate or severe hepatic impairment. | FDA label |
| Discontinuation | Withdraw gradually to minimize increased seizure frequency and status epilepticus; if rapid withdrawal is medically required, appropriate monitoring is recommended. | FDA label |
Monitoring the Diacomit label requires
| When | What | What the label says to do with it | Source |
|---|---|---|---|
| Baseline | Hematologic testing (neutrophils, platelets) | Obtain before starting | FDA label |
| Every 6 months | Hematologic testing | In controlled studies, 13% of 31 treated patients fell from normal to neutrophils below 1500 cells/mm3 and 13% to platelets below 150,000/µL; none on placebo | FDA label |
| Throughout | Weight, and growth rate in pediatric patients | Decreased appetite 46% against 10% and decreased weight 27% against 6%; in some cases, decreasing concomitant valproate by 30% per week can reduce the decrease in appetite and weight | FDA label |
| Throughout | Somnolence | 67% against 23%, all on clobazam; consider an initial 25% clobazam reduction, a further 25% if it persists, and adjustment of other sedating anticonvulsants. Caution against driving and operating machinery until the effect on alertness is known (section 5.1) | FDA label |
| Pregnancy and lactation | Counseling | Label advises recommending the North American Antiepileptic Drug Pregnancy Registry, 1-888-233-2334, with enrollment by the patient or caregiver; developmental toxicity in animals at maternal doses below the clinical dose (8.1); no data on stiripentol in human milk (8.2) | FDA label |
| Throughout | Mood, behavior, suicidality | Class AED warning; monitor for emergence or worsening of depression, suicidal thoughts or behavior, or unusual changes in mood or behavior | FDA label |
| Postmarketing | Pneumonia | Added to section 6.2 by the April 15, 2026 supplement approval | FDA letter |
Diacomit drug interactions and contraindications
| Label category | Agents and what the label says | Source |
|---|---|---|
| Clobazam | Stiripentol inhibits CYP3A4 and CYP2C19; clobazam rises about 2-fold and norclobazam about 5-fold. Consider reducing clobazam if adverse reactions occur. | FDA label |
| CYP1A2, CYP2B6 and CYP3A4 substrates | Stiripentol both inhibits and induces these enzymes in vitro; consider dose adjustment of substrates such as theophylline, caffeine, sertraline, thiotepa, midazolam, triazolam and quinidine, as clinically appropriate. | FDA label |
| CYP2C8, CYP2C19, P-gp and BCRP substrates | Consider reducing the dose of substrates such as diazepam, clopidogrel, carbamazepine, methotrexate, prazosin and glyburide if adverse reactions occur. | FDA label |
| Strong CYP1A2, CYP3A4 or CYP2C19 inducers | Rifampin, phenytoin, phenobarbital and carbamazepine may lower stiripentol concentrations; avoid concomitant use or adjust the dosage. | FDA label |
| CNS depressants and alcohol | May increase the risk of sedation and somnolence; counsel patients and caregivers to avoid alcohol during treatment. | FDA label |
| Fenfluramine (Fintepla) | Biocodex's enrollment form, citing the Fintepla label, notes that stiripentol plus clobazam raises fenfluramine concentrations and that the maximum fenfluramine dose is then 0.2mg/kg twice daily, 17mg a day. | Enrollment form |
| Policy context | Cigna's IP0409 also lists an approval path for certain other treatment-refractory epilepsies, which are outside the FDA-approved indication. | Cigna policy |
| Approval history | Drugs@FDA lists the original approval on August 20, 2018, efficacy supplement S-003 on July 14, 2022 and labeling supplement S-006 on April 15, 2026. | Drugs@FDA record |
Why a first fill stalls, and the fix
- Prior authorization pending or deniedCigna asks for age 6 months or older and a weight of 7kg (15 pounds) or more. It asks that Diacomit is prescribed by a neurologist or in consultation with one. It also asks that the patient takes clobazam, or cannot take it because of side effects. The neurologist's office documents each of these points on the request.
- The prescription went to a regular pharmacyBiocodex says Diacomit is available only through PANTHERx Rare Pharmacy. The neurologist's office can fax a Patient Enrollment Form to PANTHERx or send it an electronic prescription.
- The pharmacy is missing informationBiocodex asks offices to include the diagnosis code, the patient's weight, the formulation and quantity, and clear dosing instructions. It also asks for insurance cards, medical records and a medicine list that shows clobazam use and dose.
- Insurance approval is taking too longBiocodex's Quick Start Program can supply up to 60 days of Diacomit at no cost. It is for newly eligible patients who face delays in getting access to treatment.
- Insurance changed or lapsedBiocodex's Bridge Program can supply up to 60 days of Diacomit at no cost. It is for patients already on Diacomit whose insurance coverage changes or lapses.
- A copay you cannot payBiocodex's Copay Program offers a $0 copay per prescription for eligible patients with commercial insurance. It is not available for government plans such as Medicare or Medicaid. Our help paying page lists charity funds that may assist with costs.
- No insurance, or not enoughBiocodex's Long-Term Patient Assistance Program provides Diacomit at no cost for eligible patients who are uninsured or underinsured. The Biocodex By Your Side team at 833-248-0467 can explain eligibility.
Biocodex By Your Side Support Team at PANTHERx
- Delivery to the home from PANTHERx Rare Pharmacy, the only pharmacy that dispenses Diacomit
- Support with insurance coverage and eligibility for savings, and outreach to the prescriber for refills when needed
- Pharmacists on call 24/7 and translation services in more than 100 languages
- A Rapid Refill program for scheduling refills online or by mobile, which requires opting in, plus shipment tracking and vacation planning
- Dosing supplies by request: 10mL and 35mL oral syringes and 100mL dosing cups
- Copay Program: $0 copay per prescription for eligible patients with commercial insurance. Not available for government plans such as Medicare or Medicaid
- Quick Start Program: up to 60 days of Diacomit at no cost for newly eligible patients experiencing delays in getting access to treatment
- Bridge Program: up to 60 days of Diacomit at no cost for patients on Diacomit with changes or lapses in insurance coverage
- Long-Term Patient Assistance Program: Diacomit at no cost for eligible patients who are uninsured or underinsured
Questions prescribers' offices ask about Diacomit
What is the Diacomit dose in Dravet syndrome?
50mg/kg/day in 2 or 3 divided doses, to a maximum of 3,000mg a day, per the April 2026 label (section 2.2). Patients 6 months to under 1 year, and patients 1 year and older weighing 7kg to under 10kg, are limited to 25mg/kg twice daily. At 10kg and above and 1 year and older, the regimen is 25mg/kg twice daily or 16.67mg/kg three times daily. Round to the nearest achievable dose, usually within 50mg to 150mg of target.
What blood monitoring does the Diacomit label require?
Hematologic testing before the first dose and then every 6 months, per the April 2026 label (sections 2.1 and 5.3). Among 31 Diacomit-treated trial patients with paired counts, 13% fell from normal to a neutrophil count below 1500 cells/mm3 and 13% to a platelet count below 150,000/µL, against none on placebo.
How does Diacomit change clobazam exposure, and what does the label say to do?
Clobazam rises about 2-fold and norclobazam about 5-fold, per the April 2026 label (sections 7.1 and 12.3). If somnolence occurs, consider an initial clobazam reduction of 25%, then a further 25% if it persists, and consider adjusting other sedating anticonvulsants (section 5.1). Somnolence was 67% against 23% on placebo, with all patients on clobazam.
How do the capsule and the powder for oral suspension differ?
Both come as 250mg and 500mg units, in bottles of 60 capsules or cartons of 60 packets, per the April 2026 label (sections 3 and 16.1). Capsules are swallowed whole during a meal and should not be broken or opened. Powder is mixed in 100mL of water and taken immediately during a meal, followed by a 25mL rinse. Each 250mg packet contains 1.40mg phenylalanine and each 500mg packet 2.80mg; capsules contain none.
What do insurers ask for to approve Diacomit in Dravet syndrome?
The Cigna policy shown here, IP0409 effective May 1, 2026, asks for age 6 months or older and weight of 7kg or more, concomitant clobazam or inability to take clobazam because of adverse events, and prescribing by or in consultation with a neurologist. Approval is for 1 year, and continuation requires response as determined by the prescriber. The policy cites the July 2022 label, before the April 2026 revision that added pneumonia to postmarketing experience.
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Sources
- DIACOMIT- stiripentol capsule; DIACOMIT- stiripentol powder, for suspension: prescribing information, revised 4/2026, Medication Guide, issued 07/2022, and Instructions for Use, approved 7/2022, Biocodex, Inc., via DailyMed, 2026-04-27.
- Accessing DIACOMIT® (stiripentol), Biocodex, Inc., 2026-11-11.
- DIACOMIT® (stiripentol) Access and Coverage I HCP Site, Biocodex, Inc., 2026-11-11.
- DIACOMIT® Patient Enrollment Form (BBD-00421-052025), Biocodex, Inc., 2025-05.
- Drug Coverage Policy IP0409, Diacomit (Antiseizure Medications, Diacomit), Cigna, 2026-05-01.
- NDA 206709/S-006 and NDA 207223/S-006 supplement approval letter, postmarketing experience subsection adding pneumonia, FDA, 2026-04-15.
- Antiseizure Drug DIACOMIT Now Approved for Children as Young as 6 Months, Biocodex, Inc., via BioSpace, 2022-09-21.
- Drugs@FDA records for NDA 206709 and NDA 207223, DIACOMIT, via openFDA, FDA, 2026-11-11.
A reference drawn from the April 27, 2026 label, the drugmaker's published program and one public insurer policy shown as an example, checked on November 11, 2026. Labels and policies change; the label on DailyMed and the plan's current policy govern. Trial Friend is not a medical provider. It reports what these documents say and does not judge whether a drug is safe or right for any patient; that is the prescriber's decision. Not a substitute for the prescribing information.