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Therapeutic action
- Antiseizure (anticonvulsant)
Indications
- Second-line treatment of convulsive status epilepticus
Forms and strengths, route of administration
- 250 mg in 5 ml ampoule or vial (50 mg/ml), for IV route only, to be administered through a large central or peripheral vein.
- Dilute the solution in 0.9% sodium chloride only. DO NOT DILUTE IN GLUCOSE.
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For administration use a infusion set or line with a 0.2 micron filter.
- DO NOT ADMINISTER BY RAPID IV INJECTION.
Dosage and duration
- Loading dose:
Child and adult: 20 mg/kg (max. 2 g) single dose
|
Patients |
Mode of administration |
Duration of infusion |
Max. rate |
|---|---|---|---|
|
Children ≥ 1 month and ≤ 25 kg |
Use diluted solution: add 1 ml (50 mg) of PHT to 9 ml of 0.9% NaCl to obtain 10 ml of solution containing 5 mg of PHT per ml. Administer by IV infusion using a syringe pump(a)Citation a.Or only if syringe pump is not available, use a paediatric infusion set.. |
20 min |
1 mg/kg/min |
|
Children > 25 kg and adults |
Add undiluted solution to a 100 ml bag of 0.9% NaCl. Administer by IV infusion. |
≤ 1 g or ≤ 50 kg: 20 min |
50 mg/min |
|
> 1 g and ≤ 1.5 g or > 50 kg and ≤ 75 kg: 30 min |
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|
> 1.5 g and ≤ 2 g or > 75 kg and ≤ 100 kg: 40 min |
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|
Older patients (≥ 65 years) and adults with cardiac disorders |
Add undiluted solution to a 100 ml bag of 0.9% NaCl. Administer by IV infusion. |
≤ 1 g or ≤ 50 kg: 40 min |
25 mg/min |
|
> 1 g and ≤ 1.5 g or > 50 kg and ≤ 75 kg: 60 min |
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| > 1.5 g and ≤ 2 g or > 75 kg and ≤ 100 kg: 80 min |
- aOr only if syringe pump is not available, use a paediatric infusion set.
- If maintenance treatment is indicated after the loading dose: change to oral route as soon as possible.
Contra-indications, adverse effects, precautions
- Do not administer to patients with bradycardia or atrioventricular block.
- Administer with caution in patients with hepatic impairment (reduce dosage), heart failure, cardiac rhythm disorders, hypotension.
- May cause:
- irritation or swelling at injection site; necrosis in the event of extravasation;
- drowsiness, dizziness, headache, behavioural disturbances;
- hypotension, bradycardia, conduction disorders, when injected too rapidly;
- gastrointestinal disturbances (nausea, vomiting), hepatotoxicity;
- haematologic disorders and hypersensitivity reactions sometimes severe;
- cardiac complications and coma in the event of overdose.
- Closely monitor heart rate and blood pressure during and after administration. Reduce the infusion rate in the event of bradycardia or drop in blood pressure.
-
Avoid IV placement in the hand, foot or wrist. Closely monitor injection site, during and after administration, in particular in:
-
older or very young patients (fragile veins),
-
patients with cardiovascular disease.
-
-
Before and after infusion, flush the catheter with 0.9% NaCl to limit venous irritation and potential incompatibility with other drugs.
- Avoid or monitor the combination with:
- rifampicin, mefloquine (reduced effect of PHT);
- sulfonamides, chloramphenicol, fluconazole, isoniazid, fluoxetine, omeprazole (increased PHT toxicity);
- benzodiazepines, opioid analgesics, antipsychotics, first-generation antihistamines (hydroxyzine, promethazine), antidepressants, other antiseizure medications, etc. (increased sedation).
- PHT may reduce the effect of many drugs:
- diazepam, midazolam, digoxin, corticosteroids, antimicrobials, some antiretrovirals, itraconazole, warfarin, etc. Adjust dosage if necessary.
- implants and oral contraceptives: use condoms until next menstruation.
- Pregnancy and breast-feeding: prefer a safer drug (levetiracetam). If PHT is the only option, the risks linked to status epilepticus appear greater than risks linked to PHT.
Remarks
- Do not mix with other drugs in the same syringe or infusion.