克立馬斯汀
克立馬斯汀是一種第一代乙醇胺類抗組織胺藥物，主要用於緩解過敏症狀。其特點為具有較強的抗膽鹼作用，但鎮靜副作用較一般第一代抗組織胺低。在狗與馬的口服生體可用率極低，因此口服給藥的臨床療效受到質疑。
作用機制: Like other first-generation antihistamines, clemastine acts as a competitive antagonist (or inverse agonist) at **H1-receptors**. * **Mechanism:** Competes with histamine for H1-receptor sites on effector cells (smooth muscle, endothelium, CNS) → prevents histamine-induced bronchoconstriction, vasodilation, and increased capillary permeability. * **Note:** It does *not* block the release of histamine from mast cells or basophils, but rather antagonizes its downstream effects. * Exhibits significant **anticholinergic (antimuscarinic)** activity, which contributes to both its drying effects on mucous membranes and potential side effects.
各物種劑量
- Antihistamine · 0.68 mg per cat PO twice daily · PO · q12h
- Antihistamine · 0.34-0.68 mg per cat PO q12h · PO · q12h
- Atopy · 0.15 mg/kg PO q 12 hrs · PO · q12h · Efficacy may be increased by combining with omega 3 fatty acids.
- Allergic conditions (Historical dosing - Efficacy doubtful) · 0.05-0.1 mg/kg PO q12h · PO · q12h · Oral bioavailability is <5%. An oral dose of 0.5 mg/kg only slightly inhibited wheal formation. Further dosing studies are needed before recommending therapeutic oral use.
劑量為合格獸醫專業人員的臨床參考。請務必對照最新藥品仿單及個別病患確認。
給藥途徑
禁忌症
- Known hypersensitivity to clemastine
不良反應
- Sedation (dogs)
- Paradoxical hyperactivity (dogs)
- Anticholinergic effects: dry mucous membranes, tachycardia, urinary retention
- Diarrhea (cats)
- Fixed drug reaction (cats - rare)
藥物相互作用
- CNS Depressant Medications (e.g., barbiturates, tranquilizers) · Additive CNS depression may occur.
- Monoamine Oxidase Inhibitors (e.g., furazolidone, amitraz, selegiline) · May intensify the anticholinergic effects of clemastine.
- CNS Depressants (e.g., phenobarbital, gabapentin, opioids) · Additive CNS depression and sedation · moderate
- Anticholinergic drugs · Additive anticholinergic effects (dry mouth, urinary retention) · moderate
監測
- Clinical efficacy (reduction in pruritus, allergic signs)
- Adverse effects (sedation, hyperactivity, anticholinergic signs)
過量
There are no specific antidotes for clemastine overdose. * **Management:** Handle significant overdoses using standard gut-emptying protocols (emesis/gastric lavage) when appropriate, followed by supportive therapy. * **Clinical Signs:** Overdose signs are extensions of the drug's side effects, principally **CNS depression** (though CNS stimulation/seizures may occur), severe **anticholinergic effects** (severe drying of mucous membranes, tachycardia, urinary retention, hyperthermia), and possibly hypotension. * **Specific Treatments:** **Physostigmine** may be considered to treat serious CNS anticholinergic effects. **Diazepam** can be employed to treat seizures if necessary.
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。