VetSheet

哌唑嗪

Prazosin

Prazosin hydrochloride

Alpha-1 腎上腺素受體阻斷劑POIV狗貓

別名: Minipress · Hypovase · CP-12299-1 · furazosin hydrochloride · prazosini hydrochloridum · Prazosinum · Prazosin 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

Systemic hypertension (extra-label) — Weight-based dosage

0.5–2 mg/kgPO
  • q8-12h

NA

必須一併考量的臨床脈絡 (2)
  • Systemic hypertension (extra-label):
  • ■ This medicine may be given with or without food. If your animal vomits, stops eating, or acts sick after getting prazosin on an empty stomach, give the medicine with food or a small treat to see if this helps. If vomiting continues, contact your veterinarian.
formulary方案年份 2023審核 dose-audit-plumb-v13

劑量為合格獸醫專業人員的臨床參考。請務必對照最新仿單及個別病患確認。

正在看診？VetSheet 的 AI 會把藥物、劑量與療程直接寫入結構化的看診紀錄。了解 VetSheet 如何運作

概覽

哌唑嗪（Prazosin）是一種高度選擇性的 ​Alpha-1 腎上腺素受體阻斷劑​（交感神經抑制劑）。

在獸醫學中，雖然它曾被用作平衡型血管擴張劑（同時降低前負荷與後負荷）以輔助治療充血性心衰竭（CHF）及全身性或肺動脈高壓，但目前最主要的臨床應用是​下泌尿道疾病的管理​。

​臨床要點：​

  • ​尿道放鬆：​ 哌唑嗪能極為有效地放鬆內尿道括約肌的平滑肌。它是治療功能性尿道阻塞的常規藥物，特別適用於「尿道阻塞的貓咪」（貓自發性膀胱炎/FLUTD）以及患有反射性協調不良或前列腺疾病的犬隻。
  • ​心血管特性：​ 與肼屈嗪（Hydralazine）不同，哌唑嗪能同時擴張動脈與靜脈端，且通常不會引發反射性心搏過速或增加腎素（Renin）的釋放。

作用機轉

Prazosin competitively binds to and blocks post-synaptic alpha-1 adrenergic receptors.

  • ​Genitourinary Tract:​ Blockade of alpha-1 receptors in the trigone of the bladder and the proximal urethra → smooth muscle relaxation → decreased urethral resistance → facilitates micturition and relieves functional obstruction.
  • ​Cardiovascular System:​ Blockade of alpha-1 receptors on vascular smooth muscle → vasodilation of both arterioles and veins → decreased peripheral vascular resistance (afterload) and decreased venous return (preload) → lowered systemic blood pressure and reduced right atrial pressure.

安全性與警告

禁忌症

  • Preexisting hypotensive conditions
  • Pre-existing hypotension
  • Hypovolemia
  • Known hypersensitivity to alpha-blockers

不良反應

  • Hypotension (including orthostatic hypotension/syncope)
  • Nausea
  • Constipation
  • Tachyphylaxis (drug tolerance)
  • Hypotension (especially first-dose effect)
  • Lethargy / Weakness
  • Dizziness / Syncope
  • Gastrointestinal upset (vomiting, diarrhea)
  • Reflex tachycardia

注意事項

​MDR1/ABCB1 Mutation Warning:​ Anecdotal reports suggest dogs with the ABCB1 mutation may be overly sensitive to prazosin. Consider alternate drugs or reduce dosage and increase monitoring (especially blood pressure).

  • Use with caution in patients with chronic renal failure.
  • Use with caution in patients with preexisting hypotensive conditions.
  • ​First-Dose Effect:​ Syncope secondary to orthostatic hypotension can occur after the first dose. Monitor closely.

藥物交互作用

Beta-blocking agents (e.g., propranolol)

May enhance the postural hypotensive effects seen after the first dose of prazosin

Clonidine

May decrease prazosin antihypertensive effects

Sildenafil (and other PDE inhibitors)

May increase risk for hypotension

Verapamil or Nifedipine

May cause synergistic hypotensive effects when used concomitantly with prazosin

AmlodipineModerate

Additive hypotensive effects

ACE Inhibitors (e.g., Benazepril, Enalapril)Moderate

Increased risk of severe hypotension

Beta-blockers (e.g., Propranolol)Moderate

Exacerbation of postural hypotension

SildenafilMajor

Profound hypotension

監測

  • Baseline thoracic radiographs
  • Mucous membrane color
  • Capillary refill time (CRT)
  • Arterial blood pressure
  • Venous PO2 (if possible)
  • Systemic blood pressure
  • Heart rate
  • Urine output and ease of urination (if used for urethral spasm)

藥物動力學

半衰期

貓Unknown狗Approximately 2-3 hours

吸收

Variably absorbed after oral administration in humans. Peak levels occur in 2-3 hours.

分佈

Widely distributed throughout the body; approximately 97% bound to plasma proteins. Minimally distributed into milk. Unknown if it crosses the placenta.

代謝

Metabolized in the liver; some metabolites have pharmacologic activity.

排除

Metabolites and some unchanged drug (5-10%) are primarily eliminated in feces via the bile.

過量

Based on ASPCA APCC data (2008-2009):

  • ​Dogs:​ Common findings include hyperactivity, tachycardia, hyperthermia, panting, and agitation.
  • ​Cats:​ Common findings include tachycardia.

​Treatment:​

  • Evacuate gastric contents and administer activated charcoal using standard precautionary measures if ingestion was recent and cardiovascular status is stable.
  • Monitor heart rate and blood pressure.
  • Treat shock using volume expanders and pressor agents if necessary.
  • Monitor and support renal function.

可用產品

劑型

  • Capsules
  • 0.5 mg oral tablet
  • 1 mg oral tablet
  • 2 mg oral tablet

人用標示

  • Prazosin Capsules: 1 mg, 2 mg & 5 mg (as base); Minipress® (Pfizer); generic
  • Hypovase 0.5 mg, 1 mg, 2 mg, 5 mg tablets
  • Prazosin 0.5 mg, 1 mg, 2 mg, 5 mg tablets

各地核准狀態

European Union✓ 已核准處方藥EMA

POM (Prescription Only Medicine)

United Kingdom✓ 已核准處方藥VMD

POM (Prescription Only Medicine)

暫無法規資料: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU

儲存與穩定性

Prazosin capsules should be stored in well-closed containers at room temperature.

飼主須知

  • ​用途：​ 此藥物最常用於幫助放鬆泌尿道，使您的寵物更容易排尿（特別是剛從尿道阻塞中恢復的貓咪）。
  • ​給藥方式：​ 請嚴格按照獸醫師的指示給藥。如果可能，請將藥物與食物一起餵食。
  • ​首劑效應：​ 哌唑嗪可能會導致血壓突然下降，特別是在服用第一劑之後。您的寵物可能會出現頭暈、虛弱或嗜睡的現象。初期請避免讓牠們靠近樓梯或高處，以防摔倒。
  • ​何時應聯繫獸醫師：​ 如果寵物的狀況惡化、無法排尿，或者變得過度嗜睡或抑鬱，請立即通知您的獸醫師。

VetSheet 藥物參考供合格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商最新仿單。