賽庚啶
賽庚啶是一種具有強效抗血清素特性的第一代抗組織胺。在獸醫學中，它最常被利用的是其「仿單標示外（off-label）」的作用，而非其抗組織胺功能。 **主要獸醫臨床應用：** * **食慾促進劑：** 過去常作為貓的第一線食慾促進劑，雖然現代臨床上已多被米氮平（Mirtazapine）或 Capromorelin 取代，但在其他藥物無法取得或有禁忌症時，仍是可行的替代方案。 * **血清素症候群解毒劑：** 它是治療犬貓血清素毒性（例如誤食人類的 SSRI/SNRI 抗憂鬱藥或 5-HTP 補充劑）的**黃金標準**輔助治療藥物。 * **馬匹醫療：** 用於治療馬匹的光照性甩頭症（photic head shaking），以及作為馬匹腦下垂體中葉功能異常（PPID / 馬庫興氏症）的二線或輔助療法（儘管 Pergolide 對 PPID 的療效遠優於此藥）。 * **貓氣喘與搔癢症：** 偶爾用於貓的嗜酸性呼吸道發炎或過敏性皮膚病，但臨床療效通常有限。 > **臨床重點：** 賽庚啶需要透過肝臟代謝並經由腎臟排泄；建議在患有慢性腎病（CKD）的貓咪身上調整劑量。
作用機制: Cyproheptadine exhibits a multi-receptor antagonism profile: * **Serotonin (5-HT) Antagonism:** Competitively binds to **5-HT2A receptors** in the hypothalamus → blocks serotonin-induced satiety → stimulates appetite. In serotonin syndrome, blocking these receptors reverses life-threatening neuromuscular and autonomic hyperactivity. * **Histamine (H1) Antagonism:** Competes with histamine for **H1-receptors** on effector cells → prevents histamine-mediated capillary permeability, smooth muscle spasm, and pruritus. It does *not* prevent histamine release. * **Anticholinergic Activity:** Weakly antagonizes **muscarinic receptors** → leads to common side effects like dry mouth and urinary retention. * **Calcium Channel Blockade:** Exhibits mild calcium channel blocking properties, which may contribute to its efficacy in equine photic head shaking.
各物種劑量
- As an appetite stimulant · 2-4 mg per cat · PO · once or twice daily
- As an appetite stimulant · 1-4 mg/cat, or 0.35-1 mg/kg · PO · once or twice a day
- As an appetite stimulant · 2 mg per cat · PO · q12h
- As an appetite stimulant · 0.35-1 mg/kg · PO · q12h · May be dosed less frequently if inappetence is mild.
- As an appetite stimulant in cats with renal insufficiency · 1 mg per cat · PO · q12h
- As an antihistamine/antipruritic · 2 mg per cat · PO · q12h
- As an antihistamine/antipruritic · 2 mg per cat or 1.1 mg/kg · PO · q12h
- For feline asthma · 2 mg · PO · q12h · Particularly when cats are maxed out on dosages of corticosteroids and terbutaline. Therapeutic response may not be seen for 4-7 days, but CNS depression can occur in 24 hours.
- For adjunctive treatment of serotonin syndrome · 2-4 mg (total dose) · PO · q4-6h · until signs have resolved · In cases where PO dosing not possible (severe vomiting), may crush tablets and mix with saline and give rectally.
- Management of allergic disease / Appetite stimulation / Aortic thromboembolism · 0.1-0.5 mg/kg · PO · q8-12h
給藥途徑
禁忌症
- Hypersensitivity to cyproheptadine
- Prostatic hypertrophy
- Bladder neck obstruction
- Severe cardiac failure
- Angle-closure glaucoma
- Pyeloduodenal obstruction
- Urinary retention (relative)
- Angle-closure glaucoma (relative)
- Pyloroduodenal obstruction (relative)
不良反應
- Sedation / CNS depression
- Paradoxical hyperexcitability or agitation (especially in cats)
- Anticholinergic effects (dry mucous membranes, urinary retention, tachycardia)
- Hemolytic anemia in cats (rare)
- Polyphagia (in dogs at higher doses)
- Mild depression, anorexia, or lethargy (in horses)
- Mild sedation
- Polyphagia
- Weight gain
- Reduced seizure threshold
藥物相互作用
- CNS Depressants (barbiturates, tranquilizers, etc.) · Additive CNS depression
- SSRIs (sertraline, fluoxetine, paroxetine, etc.) · Cyproheptadine may decrease the efficacy of the SSRI due to its serotonin antagonist properties
監測
- Clinical efficacy (e.g., body weight if used for anorexia, resolution of neurologic signs if used for serotonin syndrome)
- Adverse effects (sedation, anticholinergic signs)
- Serum BUN/Creatinine in cats with long-term use
- Appetite and weight gain
- Resolution of allergic signs
- Neurological status (seizure activity)
過量
There are no specific antidotes available for cyproheptadine overdose. **Clinical Signs of Toxicity:** * Extensions of pharmacological effects: profound CNS depression (though paradoxical CNS stimulation/seizures may occur). * Severe anticholinergic effects: extreme drying of mucous membranes, tachycardia, urinary retention, hyperthermia. * Hypotension. **Management:** * **Decontamination:** Standard gut emptying protocols (emesis/activated charcoal) if caught early and patient is stable. * **Supportive Care:** IV fluids for hypotension, temperature regulation. * **Specific Interventions:** Physostigmine may be considered for life-threatening central anticholinergic effects. Diazepam should be employed to treat seizures if they occur. > *Note: Horses receiving 2x the recommended dose apparently showed no untoward effects.*
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