苯海拉明
Diphenhydramine
Diphenhydramine HCl
別名: Benadryl · Banophen · Genahist · AllerMax · Diphenhist · Dytan · Siladryl · Tusstat · Nytol · chloranautine · dimenhydrinatum · diphenhydramine teoclate · diphenhydramine theoclate · Diphenhydramine hydrochloride · DPH
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Prevaccination (extra-label)
須由已驗證獸醫確認
- once · vaccination
NA
必須同時考慮的臨床上下文 (1)
- ■ This medicine can be given either with or without food, but if an animal vomits or drools after receiving the medication on an empty stomach, try giving it with food. If vomiting continues, contact your veterinarian.
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
苯海拉明是一種在獸醫學中廣泛使用的第一代乙醇胺類抗組織胺藥物。
- 主要適應症：處理過敏反應（蕁麻疹、血管性水腫、異位性皮膚炎）、搔癢症及過敏性休克。
- 次要適應症：預防動暈症、輕度鎮靜及作為止吐藥。
臨床要點：
- 由於其容易穿透血腦屏障，與第二代抗組織胺（如西替利嗪、氯雷他定）相比，會引起更明顯的中樞神經抑制（鎮靜）作用。
- 在貓咪體內，組織胺被認為不是引發嘔吐的主要介質。因此，在治療貓咪的動暈症或嘔吐時，通常更傾向使用 NK-1 拮抗劑（如馬羅匹坦）或 M1-膽鹼能拮抗劑，而非苯海拉明。
- 有時也作為牛隻無菌性蹄葉炎及貓胰臟炎的輔助治療藥物。
作用機制
Diphenhydramine exerts its effects through multiple pathways:
- H1-Receptor Antagonism: Competitively binds to and blocks H1 receptors on effector cells → prevents histamine-mediated capillary permeability, vasodilation, and smooth muscle spasms (bronchoconstriction).
- Central Effects: Readily crosses the blood-brain barrier → blocks central H1 receptors → produces sedation and antiemetic effects.
- Anticholinergic Activity: Non-selectively binds to muscarinic receptors → decreases exocrine secretions (drying effect) and can cause urinary retention or tachycardia.
- Additional Effects: Possesses mild antitussive properties.
安全性與警告
禁忌症
- Hypersensitivity to diphenhydramine or other antihistamines in its class
- Angle closure glaucoma
- Pyloroduodenal or bladder neck obstruction
- COPD (if mucosal secretions are a problem)
- Hyperthyroidism (use with caution)
- Cardiovascular disease or hypertension (use with caution)
- Seizure disorders (use with caution)
- Known hypersensitivity to diphenhydramine
- Glaucoma (due to anticholinergic effects)
- Prostatic hypertrophy or urinary retention
- Gastrointestinal obstruction
- Use with caution in working dogs due to sedation
不良反應
- CNS depression (lethargy, somnolence)
- Anticholinergic effects (dry mouth, urinary retention)
- GI effects (diarrhea, vomiting, anorexia)
- Paradoxical excitement (especially in cats)
- Sedation/lethargy
- Dry mouth (xerostomia)
- Tachycardia
- Gastrointestinal disturbances (diarrhea, vomiting, anorexia)
注意事項
Important Warning: May mask clinical signs of ototoxicity. The sedative effects of antihistamines may adversely affect the performance of working dogs. Use with caution in pregnant or nursing animals, particularly in neonates, as the drug is excreted in milk. Liquid formulations are very distasteful to cats and may cause hypersalivation.
藥物相互作用
May potentiate anticholinergic effects
Increased sedation can occur
Additive sedation and central nervous system depression
Additive anticholinergic effects (dry mouth, tachycardia, urinary retention)
May prolong and intensify the anticholinergic effects of antihistamines
Additive CNS depression and sedation
Additive anticholinergic effects (tachycardia, dry mouth, ileus)
Increased risk of anticholinergic toxicity and sedation
監測
- Clinical efficacy (reduction in pruritus, allergic signs, or vomiting)
- Adverse effects (excessive sedation, anticholinergic signs)
- Resolution of allergic signs or pruritus
- Degree of sedation
- Heart rate (monitor for tachycardia)
- Urination frequency (monitor for retention)
藥物動力學
半衰期
吸收
Well absorbed after oral administration, but undergoes a relatively high first-pass effect. In humans, only about 40-60% reaches systemic circulation.
分佈
Reaches highest levels in the spleen, lungs, and brain. Crosses the placenta and is distributed into milk. Approximately 80% bound to plasma proteins in humans.
代謝
Metabolized in the liver.
排除
The majority of the drug is excreted as metabolites into the urine.
過量
Overdosage can cause CNS stimulation (ranging from excitement to seizures) or CNS depression (lethargy to coma), severe anticholinergic effects, respiratory depression, and death.
Treatment:
- Empty the gut after oral ingestion using standard protocols.
- Induce emesis if the patient is alert and CNS status is stable.
- Administer a saline cathartic and/or activated charcoal after emesis or gastric lavage.
- Provide symptomatic and supportive therapies.
- Seizure management: Phenytoin (IV) is recommended in humans for seizures caused by antihistamine overdose; barbiturates and diazepam should be avoided.
可用產品
劑型
- Capsules
- Chewable tablets
- Orally disintegrating tablets
- Orally disintegrating strips
- Oral liquid/syrup/elixir
- Injection
- Topical shampoo
- Topical spray
- Topical liquid
- 25 mg tablet (Oral)
- 2 mg/ml solution (Oral)
獸醫用
- Topical shampoo
- Topical spray
- Topical liquid
人用標示
- Diphenhydramine HCl Capsules and Tablets: 12.5 mg, 25 mg, 50 mg
- Diphenhydramine HCl Orally Disintegrating Tablets: 12.5 mg
- Diphenhydramine Orally Disintegrating Strips: 12.5 mg, 25 mg
- Diphenhydramine HCl Oral Liquid, Solution, Suspension, Elixir or Syrup: 12.5 mg/5 mL, 25 mg/5 mL
- Diphenhydramine Injection: 50 mg/mL
- Benadryl (various strengths)
- Nytol (various strengths)
各地核准狀態
Often used under the cascade system.
Classified as a 'P' (Pharmacy) medicine in the UK, meaning it can be purchased from a pharmacy under the supervision of a pharmacist.
暫無法規資料: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
儲存與穩定性
Store at room temperature (15-30°C). Solutions should be protected from freezing. Tablets and oral solutions should be kept in well-closed containers. Capsules and elixir should be stored in tight containers. Protect from light.
飼主須知
重要提示：未經獸醫師同意，請勿使用人類的綜合感冒或過敏藥物（這些藥物可能含有對寵物有毒的成分，如木糖醇、去鼻塞劑或止痛藥）。
- 預期反應：最常見的副作用是嗜睡或精神不振。然而，有些寵物（尤其是貓咪）可能會出現反常的興奮反應，變得過度活躍或焦躁。
- 給藥方式：液體製劑對貓咪來說味道非常苦；如果餵食液體，牠們可能會大量流口水。通常建議將錠劑或膠囊藏在零食中餵食。
- 副作用：可能會引起口乾（您可能會注意到寵物舔嘴唇或喝更多水），偶爾會出現嘔吐或腹瀉。
- 檢測注意事項：如果您的寵物安排了過敏原皮膚測試，通常需要提前幾天停用此藥物。請向您的獸醫師詢問具體指示。
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。