マロピタント
マロピタント（Cerenia®）は、犬および猫の急性嘔吐や乗り物酔いの予防・治療に広く使用される強力な**ニューロキニン-1（NK-1）受容体拮抗薬**です。制吐作用に加えて、**内臓鎮痛**効果もあり、セボフルランなどの全身麻酔薬の必要量を減少させることが知られています。
作用機序: Maropitant exerts its effects by acting as a potent and selective antagonist at the **neurokinin-1 (NK-1) receptors** in the central nervous system (specifically the emetic center and chemoreceptor trigger zone). * **Substance P Inhibition**: It competitively binds to NK-1 receptors, blocking the binding of **Substance P**, a key neuropeptide/neurotransmitter involved in the emetic pathway. * **Dual Action**: Because Substance P is the final common pathway for vomiting, maropitant effectively suppresses emesis triggered by both **central** and **peripheral** stimuli. * **Pain Modulation**: Substance P is also heavily involved in nociception; blocking its receptors in the visceral pathways provides significant visceral pain relief.
動物種別の用量
- As an antiemetic · 1 mg/kg · SC or PO · Unknown · Based on pharmacokinetic study
- As an antiemetic · 0.5-1 mg/kg · SC · once daily · up to 5 days
- Treatment of vomiting · Dose not specified in text · SC/IV · Not specified · Not specified · Treatment by injection is recommended for frequent vomiting. Very high doses may cause haemolysis.
- Prevention of acute vomiting · 1 mg/kg · SC · q24h · up to 5 consecutive days · Given at least one hour prior to anticipated emetogenic event
- Prevention of acute vomiting · 2 mg/kg · PO · q24h · up to 5 consecutive days · Given at least two hours prior to anticipated emetogenic event
- Treatment of acute vomiting · 1 mg/kg · SC · q24h · up to 5 consecutive days · If a longer duration of therapy is needed, a 48 hour washout period is recommended due to accumulation of the drug.
- Prevention of vomiting due to motion sickness · 8 mg/kg (minimum dose) · PO · q24h · up to 2 consecutive days · Given at least two hours prior to travel. If a longer duration of therapy is needed, a 72 hour washout period is recommended.
- Treatment and prevention of vomiting (including chemotherapy) · Dose not specified in text · PO/SC/IV · Not specified (duration of activity is 24 hours) · Up to 5 days · Repeat treatment at a lower dose may be adequate in some individuals. If longer periods of treatment are required, a 72-hour interval is recommended between courses.
- Motion sickness · Dose not specified in text · PO/SC/IV · Not specified · Up to 2 days · Not all preparations are specifically licensed for this purpose.
用量は獣医療従事者向けの臨床リファレンスです。必ず最新の添付文書と個々の患者で確認してください。
投与経路
禁忌
- Puppies less than 11 weeks old (due to risk of bone marrow hypoplasia)
- Suspected gastrointestinal obstruction
- Suspected gastrointestinal perforation
- Use for longer than 48 hours without a definitive diagnosis
有害事象
- Pre-travel vomiting (especially at higher motion sickness doses)
- Hypersalivation
- Pain or swelling at the subcutaneous injection site
- Diarrhea
- Anorexia
- Localized injection site reactions (cats)
- Transient pain reaction during injection (very common, especially in cats)
- Haemolysis (at very high doses in cats)
薬物相互作用
- Highly protein-bound medications · Use with caution; maropitant is highly protein-bound (99.5%) and could theoretically compete for binding sites, though clinical significance is undetermined.
- Calcium-channel antagonists · Maropitant has an affinity for calcium-channels; concurrent use should be avoided. · major
- Highly protein-bound drugs · Maropitant is highly bound to plasma proteins and may compete with other highly bound drugs, potentially altering free drug concentrations. · moderate
モニタリング
- Clinical efficacy (decreased episodes of vomiting)
- Adverse effects (e.g., injection site pain, hypersalivation)
- Resolution of vomiting
- Liver function (in patients with pre-existing hepatic disease)
- Signs of gastrointestinal obstruction or perforation
過量投与
Maropitant has a wide margin of safety. * **Dogs**: Tolerance has been confirmed at doses up to 3 times the recommended oral dose (8 mg/kg) for 3 times longer than the maximum duration. * **High-Dose Toxicity (20 mg/kg/day in dogs)**: Can cause emesis, significant body weight loss (8-15%), ECG changes (slight increases in P-R interval, P wave duration, and QRS amplitude), slightly lower serum albumin, and increased adrenal weights. * **Rodent Studies**: Doses up to 30-100 mg/kg PO caused decreased activity, irregular/labored respiration, ataxia, and tremors.
VetSheet の薬剤リファレンスは、獣医療従事者向けの臨床意思決定支援を目的としており、専門的判断やメーカーの最新添付文書に代わるものではありません。