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an anticonvulsant used in the treatment of epilepsy; administered orally.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.


Apo-Primidone (CA), Mysoline

Pharmacologic class: Barbiturate

Therapeutic class: Anticonvulsant

Pregnancy risk category NR


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


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


• Hypersensitivity to drug or phenobarbital

• Porphyria


Use cautiously in:

• hepatic, renal, or chronic obstructive pulmonary disease

• pregnant or breastfeeding patients

• hyperactive children.


• 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.

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,


Skin: flushing, rash


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.

McGraw-Hill Nurse's Drug Handbook, 7th Ed. Copyright © 2013 by The McGraw-Hill Companies, Inc. All rights reserved


Desoxyphenobarbital Neurology An anticonvulsant used as a monotherapy for partial seizures–eg, secondary generalized seizures. See Phenobarbital, Seizures.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.


An ANTICONVULSANT drug used in the treatment of EPILEPSY. A brand name is Mysoline.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005
References in periodicals archive ?
Chemical analysis of massive crystalluria following primidone overdose.
Distribution of major anticonvulsants involved in anticonvulsant exposures Female Male Total Drug No (%) No (%) No (%) Carbamazepine 13 (29.0) 12 (37.6) 25 (32.5) Valproic acid 16 (35.6) 2 (6.3) 18 (23.4) Phenytoin 4 (8.9) 9 (28.1) 13 (16.8) Oxcarbazepine 5 (11.1) 4 (12.5) 9 (11.7) Gabapentin 2 (4.4) 1 (3.1) 3 (3.9) Lamotrigine 2 (4.4) - 2 (2.6) Phenobarbital 1 (2.2) - 1 (1.3) Primidone - 1 (3.1) 1 (1.3) Topiramate 1 (2.2) - 1 (1.3) Other anticonvulsants along 1 (2.2) 1 (3.1) 2 (2.6) with carbamazepine Other anticonvulsants along - 1 (3.1) 1 (1.3) with valproic acid Other anticonvulsants along - 1 (3.1) 1 (1.3) with phenytoin Total 45 (100.0) 32 (100.0) 77 (100.0) Table 5.
Anticonvulsant drugs, including Primidone, can cause vitamin D insufficiency as an adverse drug reaction [8].
(31) The likelihood of response to oral medications such as propranolol, primidone, and some anticonvulsants is higher than SD.
Depending on the dose of primidone, sedation, dizziness, and altered consciousness have been reported, although neither previous studies nor the package insert indicated that atrial fibrillation is among its side effects.
* Anti-seizure drugs: Phenytoin (Dilantin), phenobarbital, primidone (Mysoline)
Phenobarbital, primidone, propofol secobarbital, thiobarbital Cholesterol medications Statins, bileacid-cholestyramine Chemotherapy medications Mitomycin C.
Studies have shown that phenobarbital, primidone and valproic acid work in preventing the recurrence of simple febrile seizures; however, the side effects of each medication outweigh the benefit.
(10) Besides tobacco smoke, other CYP1A2 inducers include charbroiled food, carbamazepine, omeprazole, phenobarbital, primidone, and rifampin (4), (5) Nicotine replacement products-such as gum, inhalers, lozenges, patches, and nasal spray-and nicotine delivery devices such as electronic cigarettes do not induce hepatic CYP1A2 enzymes or cause the same drug interactions as cigarette smoking.
A new evidence-based guideline issued by the American Academy of Neurology for the treatment of essential tremor reinforces the use of propranolol and primidone as the go-to agents for the disease.
A new evidence-based guideline issued by the American Academy f Neurology for the treatment of essential tremor reinforces the use of propranolol and primidone as the go-to agents for the disease.