羥嗪 (Hydroxyzine)
Hydroxyzine
Hydroxyzine hydrochloride, Hydroxyzine pamoate
別名: Atarax · Vistaril · Masmoran · Ucerax · Hydroxyzine embonate · Hydroxyzine pamoate · Hydroxyzine HCl · Hydroxyzini HCl · Hydroxyzine hydrochloride
由 VetSheet 獸醫團隊審訂更新於 2026年4月5日本內容以實證獸醫文獻為本
經審核的 v13 劑量證據
結構化劑量計算證據Antipruritic/antihistamine (extra-label)
- q8-12h
NA
必須同時考慮的臨床上下文 (2)
- ■ This medicine may be given with or without food. If your animal drools, vomits, or acts sick after receiving this medicine on an empty stomach, give with food or a small treat to see if this helps.
- Hydroxyzine oral products should be stored in tight, light-resistant containers at room temperature 20°C to 25°C (68°F-77°F). Hydroxyzine injection should be stored protected from light at room temperature 20°C to 25°C (68°F-77°F) with excursions permitted to 15°C to 30°C (59°F-86°F). Avoid freezing all liquid products.
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。
概覽
羥嗪是一種第一代抗組織胺藥物，廣泛應用於獸醫學中。主要用於其止癢和抗組織胺特性，是治療犬貓異位性皮膚炎、跳蚤過敏性皮膚炎等過敏性疾病的常用藥物。
由於它能穿透血腦屏障，因此也具有鎮靜和安神的作用，這對於焦慮或極度搔癢且有自殘傾向的動物非常有益。在貓中，由於其解痙和輕度抗焦慮特性，有時也用於管理頻繁復發的自發性下泌尿道疾病 (FLUTD)。
作用機制
Hydroxyzine acts as a competitive antagonist at H1-receptors on effector cells.
- Histamine Blockade: Competes with histamine for H1-receptor sites → prevents histamine-induced bronchoconstriction, vasodilation, and capillary permeability. Note: It does not inhibit the release of histamine from mast cells, but antagonizes its effects.
- CNS Effects: Readily crosses the blood-brain barrier → binds to central H1 receptors → causes sedation and tranquilization.
- Additional Properties: Exhibits anticholinergic, antispasmodic, local anesthetic, mild bronchodilative, and antiemetic activities.
- Metabolism Pearl: In vivo, hydroxyzine is metabolized in the liver to its active metabolite, cetirizine, which contributes significantly to its prolonged antihistaminic effects.
安全性與警告
禁忌症
- Hypersensitivity to hydroxyzine or its metabolites (e.g., cetirizine)
- Known hypersensitivity to hydroxyzine or cetirizine
- Early pregnancy (teratogenic in some animal models)
不良反應
- Sedation (most common, usually mild and transient in dogs)
- Hyperexcitability (occasional paradoxical reaction)
- Fine rapid tremors (dogs)
- Whole body tremors (dogs)
- Seizures (rare in dogs)
- Polydipsia (cats)
- Depression (cats)
- Behavioral changes (cats)
- Sedation / Lethargy
- Dry mouth
- Urinary retention
- Gastrointestinal upset
- Paradoxical excitation (rare)
注意事項
Use with caution in patients with prostatic hypertrophy, bladder neck obstruction, severe cardiac failure, angle-closure glaucoma, or pyeloduodenal obstruction due to its anticholinergic effects.
Pregnancy Warning: At doses substantially greater than those used therapeutically, hydroxyzine has been shown to be teratogenic in lab animals. Use during pregnancy (particularly during the first trimester) only when the benefits outweigh the risks (FDA Category C). It is unknown if hydroxyzine enters maternal milk, but its active metabolite cetirizine does.
藥物相互作用
Additive anticholinergic effects may occur when used concomitantly.
Additive CNS depression may be seen.
Hydroxyzine may inhibit or reverse the vasopressor effects of epinephrine; use norepinephrine or metaraminol instead.
Additive CNS depression and sedation
監測
- Efficacy (reduction in pruritus or clinical signs)
- Adverse effects (degree of sedation, excitability, or behavioral changes)
- Resolution of pruritus or allergic signs
- Adverse anticholinergic effects (e.g., monitoring urination)
藥物動力學
半衰期
吸收
Rapidly and well absorbed after oral administration.
分佈
Readily crosses the blood-brain barrier. It is unknown if hydroxyzine enters maternal milk, but its active metabolite cetirizine has been detected in milk.
代謝
Apparently metabolized in the liver (to its active metabolite, cetirizine).
排除
Effects generally persist for 6-8 hours in dogs and up to 12 hours in cats.
過量
Overdoses would be expected to cause increased sedation and perhaps hypotension. At high doses, fine rapid tremors and rarely seizures have been reported.
Common clinical signs of toxicity in dogs include:
- Hyperthermia
- Lethargy
- Tachycardia
- Trembling / Tremors
- Ataxia
- Somnolence
Treatment: There are no specific antidotes available. Gut emptying protocols should be considered with large or unknown quantity overdoses. Supportive and symptomatic treatment is recommended if necessary.
可用產品
劑型
- Oral Tablets
- Oral Syrup
- Injection
- Oral Capsules
- Oral Suspension
- 10 mg tablet
- 25 mg tablet
- 2 mg/ml syrup
人用標示
- Hydroxyzine HCl Oral Tablets: 10 mg, 25 mg, & 50 mg
- Hydroxyzine HCl Oral Syrup: 10 mg/5 mL
- Hydroxyzine HCl Injection: 25 mg/mL & 50 mg/mL
- Hydroxyzine Pamoate Oral Capsules: 25 mg, 50 mg, & 100 mg
- Hydroxyzine Pamoate Suspension: 25 mg/5 mL
- Atarax 10 mg tablets
- Atarax 25 mg tablets
- Ucerax 2 mg/ml syrup
各地核准狀態
Classified as POM (Prescription Only Medicine).
Classified as POM (Prescription Only Medicine).
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儲存與穩定性
Hydroxyzine oral products should be stored at room temperature in tight, light-resistant containers. Avoid freezing all liquid products.
飼主須知
- 常見嗜睡副作用：您的寵物在開始服藥時可能會顯得昏昏欲睡或無精打采。這是正常現象，但如果情況過於嚴重，請聯繫您的獸醫。
- 工作犬注意事項：此藥物可能會影響工作犬、獵犬或服務犬的表現和警覺性。
- 持續用藥是關鍵：抗組織胺藥物通常在規律給藥以「預防」過敏發作時效果最好，而不是等到過敏嚴重時才治療。
- 過敏測試：如果您的寵物安排了皮內過敏測試，您需要在測試前 3 到 7 天停用此藥物。請諮詢您的獸醫以確定確切的時間。
- 請勿重複給藥：如果您忘記給藥，請在想起來時補給，但絕對不要一次給予雙倍劑量。
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