Get our free Prazosin hydrochloride coupon and be eligible to receive a discount. You can reduce your Prazosin hydrochloride cost by up to 75% with our free Prazosin hydrochloride discount card. Bring it to a participating pharmacy near you to save on your prescription medication.Prazosin is in a group of drugs called alpha-adrenergic (AL-fa ad-ren-ER-jik) blockers. Prazosin relaxes your veins and arteries so that blood can more easily pass through them. Prazosin is used to treat hypertension (high blood pressure). Prazosin may also be used for other purposes not listed in this medication guide.