卡馬西平
卡馬西平（Carbamazepine）是一種二苯并氮雜䓬亞胺類衍生物，化學結構上與三環類抗憂鬱藥丙咪嗪（imipramine）相關。 > **臨床要點：** 雖然在人類醫學中廣泛用作主要的抗癲癇藥和情緒穩定劑，但其在獸醫學（特別是犬隻）中的實用性受到其快速肝臟自體誘導（autoinduction）的嚴重限制。犬隻在治療幾天後代謝該藥物的速度極快，使得維持治療血清濃度變得極其困難。 由於這種藥代動力學的限制，它很少用於動物的癲癇控制。相反，在獸醫學中，它主要保留用於： * 犬隻的**行為醫學**（例如，控制杏仁核過度活躍或爆發性攻擊行為，通常與 SSRI 併用）。 * 馬匹的**神經病理性疼痛**或特定的神經系統疾病，如對賽庚啶（cyproheptadine）等其他治療無效的**光照性甩頭症（photic head shaking）**。
作用機制: Carbamazepine primarily acts by **blocking voltage-gated sodium channels** in neuronal membranes. * **Mechanism:** Binds preferentially to the inactive state of sodium channels → delays their recovery → **inhibits repetitive neuronal firing** and stabilizes hyperexcited neural membranes. * It also decreases the synaptic transmission of excitatory impulses and may reduce the release of the excitatory neurotransmitter glutamate. * Structurally related to tricyclic antidepressants, it also possesses mild anticholinergic, antidiuretic, and muscle relaxant properties.
各物種劑量
- For photic head shaking · 10 mg/kg PO q6h or 29 mg/kg PO q12h · PO · q6h or q12h · May be helpful in some horses that do not respond to cyproheptadine.
- As a psychotherapeutic agent · 4-8 mg/kg PO q12h · PO · q12h · Not commonly used, but may have some utility in dogs that seem to have amygdalar hyperactivity; sometimes used in conjunction with SSRIs to control explosive aggression.
劑量為持牌獸醫專業人員的臨床參考。請務必對照最新藥品說明書及個別病患確認。
給藥途徑
禁忌症
- Patients receiving MAO Inhibitors (e.g., selegiline) within the past 14 days
- Patients with a history of bone marrow depression
- Known hypersensitivity to carbamazepine or tricyclic antidepressants
不良反應
- Sedation and lethargy
- Ataxia (unsteadiness)
- Gastrointestinal upset (vomiting, anorexia)
- Hepatotoxicity (elevated liver enzymes)
- Blood dyscrasias (rare but possible bone marrow suppression)
藥物相互作用
- Azole Antifungals (e.g., Ketoconazole, Itraconazole) · May increase plasma levels or effects of carbamazepine
- Calcium Channel Blockers (e.g., Diltiazem, Verapamil) · May increase plasma levels or effects of carbamazepine; Carbamazepine may also decrease their effects
- Cimetidine · May increase plasma levels or effects of carbamazepine
- Danazol · May increase plasma levels or effects of carbamazepine
- Grapefruit Juice · May increase plasma levels or effects of carbamazepine
- Isoniazid · May increase plasma levels or effects of carbamazepine; Carbamazepine may also increase effects of Isoniazid
- Macrolides (e.g., Erythromycin, Clarithromycin) · May increase plasma levels or effects of carbamazepine
- MAO Inhibitors (e.g., Selegiline) · Contraindicated; discontinue MAOI at least 14 days prior to carbamazepine
- Niacin · May increase plasma levels or effects of carbamazepine
- SSRI Antidepressants (e.g., Fluoxetine) · May increase plasma levels or effects of carbamazepine
- Tricyclic Antidepressants (e.g., Clomipramine, Amitriptyline) · May increase plasma levels or effects of carbamazepine; Carbamazepine may also decrease their effects, though it can increase Clomipramine levels
監測
- Complete Blood Count (CBC)
- Liver function tests
- Clinical efficacy and behavioral changes
過量
Overdose can lead to significant CNS depression, severe ataxia, tremors, seizures, respiratory depression, and cardiovascular abnormalities (tachycardia, hypotension). Treatment is primarily supportive and symptomatic, including gastric decontamination if caught early, IV fluids, and respiratory support. Seizures should be treated with standard anticonvulsants (e.g., diazepam, phenobarbital).
VetSheet 藥物參考供持牌獸醫專業人員作臨床決策輔助之用,不能取代專業判斷或廠方最新藥品說明書。