Prazosin Side Effects are rare at lower dosage that is commonly used. Prazosin is generally well tolerated at low doses. One of the most common prazosin side effects is Postural hypotension. Apart from postural hypotension related symptoms (to which tolerance frequently develops), other side effects are headache, drowsiness, dry mouth, weakness, palpitation, nasal blockade, blurred vision and rash. Ejaculation may be impaired in males: especially with higher doses. Fluid retention attending prazosin monotherapy may precipitate CHF.
Prazosin is a moderately potent antihypertensive with many desirable features, but is not used as a first line drug because of prazosin side effects like fluid retention and tolerance gradually develops with mono- therapy—necessitating dose increase—more side effects and risk of CHF. It maybe added to a diuretic + beta blocker in those not achieving target BP.
An oral dose produces peak fall in BP after 4-5 hours and the effect lasts for nearly 12 hours, though plasma t½ is only 3 hours. This may be due to generation of active metabolites that cause prazosin side effects.
Other advantages of prazosin are:
1. Improves carbohydrate metabolism; suitable for diabetics, but not if neuropathy is present – postural hypotension is accentuated.
2. Has favourable effect on lipid profile: lowers LDL cholesterol and triglycerides, increases HDL.
3. Affords symptomatic improvement in coexisting PVD or benign prostatic hypertrophy.
MINIPRESS XL: Prazosin GuS 2.5 mg, 5 mg tabs.; PRAZOPRESS 1, 2 mg tabs.