primidone (redirected from Resimatil)

primidone /prim·i·done/ (prim´ĭ-dōn) an anticonvulsant used in the treatment of generalized tonic-clonic, nocturnal myoclonic, and partial seizures.

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primidone

[prī′mədōn]

an anticonvulsant.

indications It is prescribed in the treatment of seizure disorders, including tonic-clonic, psychomotor, and focal epilepsy-like seizures, and has an unlabeled use for treating familial (essential) tremor.

contraindications Porphyria, pregnancy, or known hypersensitivity to this drug or to phenobarbital, a metabolite of primidone, prohibits its use. The drug must be used with caution in those having renal, hepatic, or pulmonary insufficiency.

adverse effects The most serious adverse effect, seen on rare occasions, is megaloblastic anemia. Drowsiness, ataxia, and dizziness are common. Drug dependency and other adverse effects of phenobarbital may occur.

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primidone

an anticonvulsant related to phenobarbital. Used in dogs to control seizures of epilepsy and encephalitis.

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primidone

Apo-Primidone (CA), Mysoline, PMS-Primidone (CA), Sertan (CA)

Pharmacologic class: Barbiturate

Therapeutic class: Anticonvulsant

Pregnancy risk category NR

Action

Unknown. May raise seizure threshold by decreasing neuronal firing after being converted to phenobarbital.

Availability

Suspension: 250 mg/5 ml

Tablets: 50 mg, 250 mg

⊘Indications and dosages

➣ Grand mal, psychomotor, or focal epileptic seizures

Adults and children ages 8 and older: Initially, 100 to 125 mg P.O. at bedtime on days 1 to 3, then 100 to 125 mg P.O. b.i.d. on days 4 to 6, then 100 to 125 mg P.O. t.i.d. on days 7 to 9, followed by a maintenance dosage of 250 mg P.O. three or four times daily

Children younger than age 8: Initially, 50 mg P.O. at bedtime on days 1 to 3, then 50 mg P.O. b.i.d. on days 4 to 6, then 100 mg P.O. b.i.d. on days 7 to 9. For maintenance, 125 to 250 mg t.i.d. or 10 to 25 mg/kg/day in divided doses.

Dosage adjustment

• Renal impairment

Off-label uses

• Benign familial (essential) tremor

Contraindications

• Hypersensitivity to drug or phenobarbital
• Porphyria

Precautions

Use cautiously in:
• hepatic, renal, or chronic obstructive pulmonary disease
• pregnant or breastfeeding patients
• hyperactive children.

Administration

• Don't change brands. Bioequivalency problems have occurred.
☞ Don't stop therapy suddenly. Dosage must be tapered.
• Know that drug may be given alone or with other anticonvulsants.

Route	Onset	Peak	Duration
P.O.	Unknown	3-4 hr	Unknown

Adverse reactions

CNS: headache, dizziness, stimulation, drowsiness, sedation, confusion, hallucinations, psychosis, ataxia, vertigo, hyperirritability, emotional disturbances, paranoid symptoms, coma

EENT: diplopia, nystagmus, eyelid edema

GI: nausea, vomiting, anorexia

GU: erectile dysfunction

Hematologic: megaloblastic anemia, thrombocytopenia

Skin: flushing, rash

Interactions

Drug-drug. Acetazolamide, succinimide: decreased primidone blood level

Carbamazepine: decreased primidone blood level, increased carbamazepine blood level

Hydantoins, isoniazid, nicotinamide: increased primidone blood level

Drug-diagnostic tests. Hemoglobin, platelets: decreased levels

Liver function tests: altered results

Patient monitoring

• Monitor primidone and phenobarbital blood levels.
• Monitor CBC and blood chemistry. Watch for evidence of blood dyscrasias.
• Assess neurologic status regularly. Stay alert for excessive drowsiness and emotional status changes.

Patient teaching

☞ Caution patient not to discontinue therapy suddenly. Advise him to discuss dosage changes with prescriber.
☞ Instruct patient to immediately report unusual bleeding, bruising, or rash.
• Tell patient drug may cause sexual dysfunction. Advise him to discuss this issue with prescriber.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration, vision, and alertness.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs and tests mentioned above.

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primidone

Desoxyphenobarbital Neurology An anticonvulsant used as a monotherapy for partial seizures–eg, secondary generalized seizures. See Phenobarbital, Seizures.