馬來酸吡拉明 (美吡拉敏)
Pyrilamine Maleate
Pyrilamine maleate (Mepyramine maleate)
別名: Histall · Equiphed · Anihist · Alergitanil · Antemesyl · Anthisan · Equi-Phar Equi-Hist · Fluidasa · Histagranules · Histamed · Mepyraderm · Mepyrimal · Pyriped · Relaxa-Tabs · TriHist · pyranisamine hydrochloride · pyrilamine hydrochloride · mepyramine hydrochloride · mepyramini maleas · myranisamine maleate · myrilamine maleate · mepyramine maleate
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
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。
各物種劑量
🌎 NA — North America🌍 EU — Europe
狗
| 適應症 | 劑量 | 途徑 | 頻次 | 療程 | 地區 |
|---|---|---|---|---|---|
| Antihistamine | 12.5-25 mg PO four times a day | PO | q6h | — | 🌎 NA |
| Antihistamine | 25-125 mg IM | IM | Unknown | — | 🌎 NA |
馬
| 適應症 | 劑量 | 途徑 | 頻次 | 療程 | 地區 |
|---|---|---|---|---|---|
| Antihistamine | 0.88-1.32 mg/kg (2-3 mL of 20 mg/mL solution per 100 lbs body weight) IV (slowly), IM or SC | IV, IM, SC | q6-12h | — | 🌎 NA |
| Antihistamine (Foals) | 0.44 mg/kg (1 mL of 20 mg/mL solution per 100 lbs. body weight) IV (slowly), IM or SC | IV, IM, SC | q6-12h | — | 🌎 NA |
| Antihistamine | 1 mg/kg IV , IM or SC | IV, IM, SC | Unknown | — | 🌎 NA |
| Antihistamine | 0.5-1.5 grams IM | IM | Unknown | — | 🌎 NA |
- Antihistamine: May repeat in 6-12 hours if necessary. NOTE: ARCI UCGFS CLASS 3 DRUG
- Antihistamine (Foals): May repeat in 6-12 hours if necessary.
牛
| 適應症 | 劑量 | 途徑 | 頻次 | 療程 | 地區 |
|---|---|---|---|---|---|
| Antihistamine | 0.5-1.5 grams IM | IM | Unknown | — | 🌎 NA |
| Adjunctive treatment of aseptic laminitis | 55-110 mg/100 kg IV or IM | IV, IM | Unknown | — | 🌎 NA |
豬
| 適應症 | 劑量 | 途徑 | 頻次 | 療程 | 地區 |
|---|---|---|---|---|---|
| Antihistamine | 0.25-0.5 gram IM | IM | Unknown | — | 🌎 NA |
羊
| 適應症 | 劑量 | 途徑 | 頻次 | 療程 | 地區 |
|---|---|---|---|---|---|
| Antihistamine | 0.25-0.5 gram IM | IM | Unknown | — | 🌎 NA |
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
馬來酸吡拉明（又稱美吡拉敏）是一種第一代乙二胺類抗組織胺藥物，在獸醫學中主要用於減少或預防組織胺介導的不良反應。
主要臨床重點：
- 主要用途：主要用於馬匹，以控制過敏性疾病，如昆蟲叮咬過敏、蕁麻疹，並作為馬氣喘（heaves）等呼吸道疾病的輔助治療。
- 優點：與其他第一代抗組織胺藥物（如苯海拉明）相比，吡拉明的鎮靜作用較弱，且抗膽鹼能副作用較少。
- 劑型：通常以複方產品（例如與偽麻黃鹼或癒創甘油醚結合）的口服顆粒劑形式用於馬匹，或作為注射液使用。
- 法規注意事項：在馬術運動中，它被歸類為 ARCI 第 3 類藥物，在比賽前需要適當的停藥期。
作用機制
Pyrilamine acts as a competitive antagonist (inverse agonist) at H1-receptors.
- Mechanism: Allergic trigger → Mast cell degranulation → Histamine release. Pyrilamine competes with free histamine for binding sites on H1-receptors located on smooth muscle, endothelium, and in the CNS.
- Effects: By blocking these receptors, it prevents histamine-induced bronchoconstriction, vasodilation, and increased capillary permeability (which leads to edema/hives).
- Limitations: It does not inhibit the release of histamine from mast cells, nor does it inactivate histamine that is already bound. Therefore, it is more effective as a preventative rather than a rescue treatment during acute anaphylaxis.
- Secondary Actions: Like other first-generation antihistamines, it can cross the blood-brain barrier, leading to mild CNS depression (sedation) or paradoxical CNS stimulation, and possesses mild anticholinergic properties.
安全性與警告
禁忌症
- Should not supersede the use of other emergency drugs and procedures (e.g., epinephrine for acute anaphylaxis)
不良反應
- CNS stimulation (nervousness, insomnia, convulsions, tremors, ataxia)
- Palpitation
- GI disturbances
- CNS depression (sedation)
- Muscular weakness
- Anorexia
- Lassitude
- Incoordination
注意事項
Emergency Use Warning: Antihistamines are not a substitute for epinephrine and supportive care in cases of severe, acute anaphylaxis.
- Skin Testing: Antihistamines suppress the wheal and flare response. Discontinue at least 4 days prior to intradermal allergy testing.
- Pregnancy: Probably safe at usual doses, though high-dose rodent studies showed increased fetal death. No teratogenic effects noted in human studies.
- Nursing: Unknown if it enters milk.
- Regulatory: Products containing pseudoephedrine are subject to strict regulations (List 1 chemical) due to illicit methamphetamine manufacturing. Pyrilamine is an ARCI Class 3 drug in racing horses.
藥物相互作用
Antihistamines may partially counteract the anticoagulation effects of heparin or warfarin.
Increased sedation can occur if pyrilamine is combined with other CNS depressant drugs.
Pyrilamine may enhance the effects of epinephrine.
監測
- Clinical efficacy (reduction in allergic signs, hives, or respiratory effort)
- Adverse effects (monitor for signs of CNS stimulation or excessive sedation)
藥物動力學
半衰期
吸收
In horses, pyrilamine is poorly bioavailable (18%) after oral administration.
分佈
Not extensively studied in cattle, dogs, or cats.
代謝
The principle metabolite is O-desmethylpyrilamine (O-DMP).
排除
After a single dose, O-DMP can be detected in urine for at least two days, and possibly up to one week after dosing.
過量
Treatment of overdosage is supportive and symptomatic.
- Seizure Management: Phenytoin (IV) is recommended in the treatment of seizures caused by antihistamine overdose in humans. Most toxicologists recommend avoiding barbiturates and diazepam, though one veterinary manufacturer historically suggested 'careful titration' of barbiturates.
- CNS Depression: Avoid the use of CNS stimulants (analeptics like caffeine, ephedrine, or amphetamines) to treat CNS depression, as this can exacerbate toxicity.
可用產品
劑型
- Granules
- Injection
- Oral Syrup (combination products)
獸醫用
- Pyrilamine Granules: 600 mg/oz (Histall)
- Pseudoephedrine HCl 600 mg/oz and Pyrilamine maleate 600 mg/oz Granules (Equiphed, Equi-Phar Equi-Hist 1200 Granules, Tri-Hist Granules, Histagranules)
- Pyrilamine 600 mg/oz and Guaifenesin 2400 mg/oz Granules (Anihist, Hist-EQ)
- Combination cough syrups containing pyrilamine labeled for use in small animals
各地核准狀態
暫無法規資料: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
儲存與穩定性
Avoid freezing the injectable product.
飼主須知
吡拉明是一種抗組織胺藥物，主要用於治療馬匹的過敏反應、蕁麻疹和呼吸道過敏。
- 預期效果：它有助於減少腫脹、發癢和過敏性呼吸道反應。
- 副作用：請密切觀察動物的行為變化。有些動物可能會變得異常嗜睡（鎮靜），而其他動物（尤其是馬）可能會變得緊張、興奮或步態不穩。如果您發現肌肉無力、震顫或食慾不振，請聯繫您的獸醫。
- 競賽馬匹：如果您的馬匹需要參加比賽，請注意此藥物受到管制（ARCI 第 3 類）。請勿在體育賽事發生前 72 小時內使用，並諮詢相關管理機構關於停藥期的規定。
- 過敏測試：如果您的寵物已安排進行皮膚過敏測試，必須在測試前至少 4 天停用此藥物。
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