프리미돈
Primidone
5-ethyldihydro-5-phenyl-4,6(1H,5H)-pyrimidinedione
다른 이름: Mysoline · Neurosyn · hexamidinum · primaclone · primidonum · Cyral · Epidona · Liskantin · Mylepsinum · Prysoline · Resimatil · Sertan
VetSheet 수의사 팀 검수업데이트 2026년 4월 5일근거 기반 수의학 참고자료
용량은 수의사 전문가를 위한 임상 참고자료입니다. 반드시 최신 약물 정보 및 개별 환자에 따라 확인하시기 바랍니다.
동물 종별 용량
🌎 NA — North America🌍 EU — Europe
개
| 적응증 | 용량 | 경로 | 빈도 | 기간 | 지역 |
|---|---|---|---|---|---|
| Seizure control | 10-30 mg/kg per day divided into 2-3 doses | PO | divided into 2-3 doses | — | 🌎 NA |
| Seizure control | 10 mg/kg | PO | q8h | — | 🌎 NA |
- Seizure control: Initially
- Seizure control: Not recommended as first choice
고양이
| 적응증 | 용량 | 경로 | 빈도 | 기간 | 지역 |
|---|---|---|---|---|---|
| Seizure control | 20 mg/kg | PO | q12h | — | 🌎 NA |
- Seizure control: Extreme caution advised; many consider contraindicated in cats.
용량은 수의사 전문가를 위한 임상 참고자료입니다. 반드시 최신 약물 정보 및 개별 환자에 따라 확인하시기 바랍니다.
개요
프리미돈은 바르비투르산염 유도체 항경련제로 주로 전구약물로 작용하며, 개에서 페노바르비탈(phenobarbital)과 페닐에틸말론아마이드(PEMA)로 빠르게 변환됩니다.
과거에는 개의 발작 조절에 사용되었으나, 현재 대부분의 수의 신경학자들은 이를 1차 선택약으로 권장하지 않습니다.
임상 팁: 페노바르비탈에 비해 심각한 간독성 발생률이 높다는 점이 장기 치료의 주요 제한 요소입니다.
개에서 프리미돈이 페노바르비탈로 변환되는 비율은 약 4:1입니다(프리미돈 250mg은 페노바르비탈 약 60mg과 유사). 일부 임상가들은 PEMA 대사체가 페노바르비탈의 항경련 활성을 강화할 수 있다는 이론에 따라 페노바르비탈 단독으로 효과가 없는 난치성 케이스에 한해 프리미돈을 사용하기도 합니다. 고양이와 토끼에게는 매우 독성이 강한 것으로 간주됩니다.
작용 기전
Primidone and its active metabolites, phenylethylmalonamide (PEMA) and phenobarbital, exert anticonvulsant effects by raising seizure thresholds and altering seizure patterns.
Mechanistic Pathway:
- Phenobarbital (Primary active metabolite): Binds to the allosteric barbiturate site on GABA_A receptors in the CNS → prolongs the duration of chloride channel opening → increases intracellular chloride influx → hyperpolarizes the postsynaptic neuron → globally depresses CNS excitability and raises the seizure threshold.
- PEMA: Has weak intrinsic anticonvulsant activity but is believed to synergistically potentiate the effects of phenobarbital.
- Primidone (Parent drug): May have some independent action on voltage-gated sodium channels, though its primary efficacy in veterinary species is attributed to its phenobarbital metabolite.
안전성·주의사항
금기사항
- Severe liver disease
- Demonstrated previous hypersensitivity to primidone or barbiturates
- Nephritis (large doses contraindicated)
- Severe respiratory dysfunction (large doses contraindicated)
- Cats (considered contraindicated by many clinicians due to high toxicity risk)
부작용
- Anxiety and agitation (especially during initiation)
- Elevated liver enzymes (ALT, ALP, GLDH)
- Decreased serum albumin
- Hepatic lipidosis
- Hepatocellular hypertrophy and necrosis
- Extramedullary hematopoiesis
- Depression and sedation
- Ataxia
- Polydipsia (PD)
- Polyuria (PU)
- Polyphagia
- Anorexia
- Tachycardia
- Dermatitis
- Episodic hyperventilation
- Urolith formation (primidone uroliths reported)
- Megaloblastic anemia (rare)
주의
Species Warnings: Use with extreme caution, if at all, in cats. Primidone is considered highly toxic to felines.
Patient Conditions: Use cautiously in patients who are hypovolemic, anemic, have borderline hypoadrenal function, or have cardiac or respiratory disease.
Drug Transition: When converting dogs from primidone to phenobarbital, it is suggested to do this slowly (tapering 1/4 of the dose each month) to prevent withdrawal seizures.
Laboratory Interference: Barbiturates may cause falsely elevated bromosulfophthalein (BSP) retention. Primidone/phenobarbital can alter thyroid testing (decreased total and free T4, normal T3, normal/increased TSH); wait at least 4 weeks after discontinuation to perform thyroid testing. May cause a false-positive low-dose dexamethasone suppression test.
약물 상호작용
Increased risk for hepatotoxicity, particularly with large or chronic doses of barbiturates.
Oral administration may decrease the GI absorption of primidone.
May prolong phenobarbital effects.
Barbiturates may affect phenytoin metabolism, and phenytoin may alter barbiturate levels; therapeutic monitoring indicated.
May induce enzymes that increase the metabolism of barbiturates.
May increase the CNS depressant effects of phenobarbital.
May increase the effects of phenobarbital; phenobarbital may also decrease chloramphenicol levels.
May increase the CNS depressant effects of phenobarbital.
May increase the effects of phenobarbital; phenobarbital may decrease phenothiazine serum concentrations.
May increase the effects of phenobarbital.
Phenobarbital may decrease anticoagulant effects by lowering serum concentrations.
Phenobarbital may decrease effects by lowering serum concentrations.
Phenobarbital may decrease effects by lowering serum concentrations.
Phenobarbital may decrease effects by lowering serum concentrations.
Phenobarbital may decrease effects by lowering serum concentrations (effect may persist for weeks after barbiturate is discontinued).
Phenobarbital may decrease effects by lowering serum concentrations.
모니터링
- Anticonvulsant efficacy (seizure frequency and severity)
- Adverse effects (CNS depression, PU/PD, weight gain, signs of liver disease)
- Serum phenobarbital levels (therapeutic range in dogs thought to be 15-40 mcg/mL) if lack of efficacy or adverse reactions are noted
- Routine CBCs and liver enzyme panels at least every 6 months during chronic therapy
약동학
반감기
흡수
Slowly absorbed after oral administration in the dog, with peak levels occurring 2-4 hours after dosing. Bioavailability in humans is reported as 60-80%.
분포
Appears in maternal milk in substantial quantities.
대사
Rapidly converted to phenylethylmalonamide (PEMA) and phenobarbital in the dog. Induces hepatic microsomal enzymes, increasing the rate of metabolism of itself and other drugs.
배설
Eliminated primarily via hepatic metabolism to active metabolites, which are subsequently cleared.
과다투여
Clinical Signs: Because primidone is rapidly metabolized to phenobarbital in dogs, signs of acute toxicity mirror barbiturate overdose: sedation progressing to coma, anorexia, vomiting, ataxia, and nystagmus.
Treatment:
- Decontamination: Removal of ingested product from the gut if appropriate (emesis or gastric lavage).
- Adsorbents: Activated charcoal is of considerable benefit in enhancing the clearance of phenobarbital (acts as a 'sink' for the drug to diffuse from the vasculature back into the gut), even if the drug was administered parenterally.
- Supportive Care: Provide respiratory and cardiovascular support.
- Enhanced Elimination: Forced alkaline diuresis can augment elimination in patients with normal renal function. Peritoneal dialysis or hemodialysis may be helpful in severe intoxications or anuric patients.
제품
제형
- Tablets
- Oral suspension
동물용의약품
- Primidone Tablets: 50 mg and 250 mg (Neurosyn®)
인용의약품
- Primidone Tablets: 50 mg and 250 mg (Mysoline®, generic)
규제 현황
규제 데이터 없음: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
보관·안정성
Tablets should be stored in well-closed containers, preferably at room temperature. Oral suspension should be stored in tight, light-resistant containers at room temperature; avoid freezing. Commercially available products generally have a 5-year expiration date.
보호자 정보
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