ペニシリンVカリウム
Penicillin V Potassium
Phenoxymethylpenicillin potassium
別名: Veetids · fenoximetilpenicilina · penicillin phenoxymethyl · phenomycilline · phenoxymethylpenicillinum
VetSheet 獣医チームが監修更新日 2026年4月5日エビデンスに基づく獣医学リファレンス
用量は獣医専門家向けの臨床参考資料です。必ず最新の医薬品情報および個別症例に基づいて確認してください。
動物種別用量
🌎 NA — North America🌍 EU — Europe
犬
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Susceptible infections | 5.5-11 mg/kg | PO | q6-8h | — | 🌎 NA |
| Soft tissue infections | 10 mg/kg | PO | q8h | 7 days | 🌎 NA |
猫
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Susceptible infections | 5.5-11 mg/kg | PO | q6-8h | — | 🌎 NA |
| Soft tissue infections | 10 mg/kg | PO | q8h | 7 days | 🌎 NA |
馬
| 適応 | 用量 | 経路 | 頻度 | 期間 | 地域 |
|---|---|---|---|---|---|
| Susceptible infections | 110,000 U/kg (68.75 mg/kg) | PO | q8h | — | 🌎 NA |
| Susceptible infections | 110,000 U/kg | PO | q6-12h | — | 🌎 NA |
- Susceptible infections: May yield supra-optimal levels against uncomplicated infections by sensitive organisms
用量は獣医専門家向けの臨床参考資料です。必ず最新の医薬品情報および個別症例に基づいて確認してください。
概要
ペニシリンVカリウムは、天然の狭域スペクトルβ-ラクタム系抗生物質です。ペニシリンGと比較して胃酸に対する耐性が高く、単胃動物における経口投与での吸収に優れています。
作用機序
Penicillin V is a time-dependent, bactericidal antibiotic.
It works by targeting the bacterial cell wall:
- Binds to specific penicillin-binding proteins (PBPs) (such as transpeptidases and carboxypeptidases) located inside the bacterial cytoplasmic membrane.
- Inhibits the third and final stage of bacterial cell wall synthesis by preventing the cross-linking of peptidoglycan strands.
- This leads to a defective, osmotically unstable cell wall (spheroplast) → cell lysis and death.
Note: Like all beta-lactams, it is only effective against actively growing and dividing bacteria.
安全性・警告
禁忌
- Known hypersensitivity to penicillins
- Oral administration in patients with septicemia, shock, or grave illness (due to delayed/diminished GI absorption)
- Use in sensitive species (snakes, birds, turtles, guinea pigs, chinchillas) without extreme caution
有害事象
- GI effects (anorexia, vomiting, diarrhea)
- Hypersensitivity reactions (rashes, fever, eosinophilia, anaphylaxis)
- Antibiotic-associated diarrhea and superinfections (due to altered gut flora)
- Neurotoxicity (e.g., ataxia in dogs) at very high doses
- Elevated liver enzymes
- Tachypnea, dyspnea, edema, and tachycardia (reported in dogs)
注意事項
Use with caution in patients with documented hypersensitivity to other beta-lactam antibiotics (e.g., cephalosporins, carbapenems) due to potential cross-reactivity. High doses of potassium salts can cause electrolyte imbalances, particularly in small animals with preexisting renal disease, congestive heart failure, or electrolyte abnormalities. Safe use during pregnancy is not firmly established (FDA Category B), and it is excreted in maternal milk, which could cause diarrhea or candidiasis in nursing offspring.
医薬品相互作用
In vitro synergism against certain bacteria; however, mixing them in the same syringe or fluid line can cause physical inactivation of the aminoglycoside.
May antagonize the bactericidal activity of penicillins, which require actively dividing bacteria to be effective.
Penicillins may decrease the renal elimination of methotrexate, potentially increasing its toxicity.
Competitively blocks the renal tubular secretion of penicillins, significantly increasing their serum levels and half-lives.
監視
- Clinical efficacy (resolution of infection signs)
- Adverse GI effects
- Signs of hypersensitivity or allergic reaction
薬物動態
半減期
吸収
Significantly more resistant to acid-catalyzed inactivation in the gut compared to Penicillin G. Oral bioavailability is 60-73% in humans, but only 30% in calves. In dogs, food decreases the rate and extent of absorption.
分布
Distributes widely into tissues. Bound to plasma proteins to a larger extent than Penicillin G (approximately 80%). Crosses the placenta and is excreted in maternal milk.
代謝
Minimal hepatic metabolism.
消失
Excreted rapidly in the urine via the kidneys (tubular secretion and glomerular filtration).
過剰投与
Acute oral overdoses are unlikely to cause significant problems other than gastrointestinal distress (vomiting, diarrhea). In humans, massive overdoses of parenteral penicillins (especially in patients with renal impairment) have induced CNS effects and seizures. Treatment is supportive.
製品
製剤
- Tablets
- Powder for oral solution
ヒト用医薬品
- Penicillin V Potassium Tablets: 250 mg & 500 mg (Veetids, generic)
- Penicillin V Potassium Powder for Oral Solution: 25 mg/mL & 50 mg/mL in 100 mL & 200 mL (Veetids, generic)
規制ステータス
規制データなし: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
保管・安定性
Tablets and powder for oral solution should be stored in tight containers at room temperature (15-30°C). After reconstitution, the oral solution must be stored in the refrigerator (2-8°C) and any unused portion discarded after 14 days.
飼主向け情報
この薬は空腹時（食前1時間または食後2時間）に与えてください。シロップ剤の場合は冷蔵庫で保管し、14日経過した残りは破棄してください。激しい下痢やアレルギー症状が見られた場合は獣医師にご相談ください。
VetSheet医薬品リファレンスは獣医専門家の臨床意思決定支援を目的としており、専門的判断または製造業者の最新医薬品情報の代替にはなりません。