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Clinical pharmacy 2024/2025 Level 3 Pharm D Pharmacology 1 (PO 502)

4- Prazosin: selective α1 blocker

 In addition, it has a direct vasodilator action (without receptor)
direct vasodilator اهنأو blocker اهنا نيب قرف ف
 Not produce significant tachycardia (less than non-selective).

➢ Mild to moderate hypertension.
Uses ➢ Severe congestive heart failure. Due to decrease resistance ( afterload)

➢ Impaired bladder emptying caused by prostatic obstruction.
➢ First-dose syncope (or effect) ةعرج لوا دعب هيلع ىمغي➔ dose related postural
hypotension ➔ occurs within 2 hours of the initial dose ➔ so, starts with a
single dose at bedtime & stop diuretics & β-blockers at the start of the

treatment.
➢ Dizziness, headache and lassitude. لسك
➢ Chronic use may cause sodium and fluid retention due to stimulation

Side angiotensin II
effects

5- Other selective α1-blockers

Terazosin and Doxazocin ➔ Trimazosin & Indoramin ➔ similar to
long acting selective α 1 blockers prazosin but do not show first dose syncope.

Tamsulosin➔ for BPH

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