Doxazosin Mesylate

Doxazosin mesylate tablets are an alpha 1 adrenergic antagonist indicated for: ( 1 ) Signs and symptoms of Benign Prostatic Hyperplasia (BPH) Treatment of Hypertension

The use of doxazosin mesylate is contraindicated in patients with a hypersensitivity to doxazosin, other quinazolines (e.g., prazosin, terazosin), or any of its components. Hypersensitivity to doxazosin, other quinazolines, or any other ingredient in doxazosin mesylate tablets. ( 4 )

Postural hypotension with or without syncope may occur. ( 5.1 ) Risk of Intraoperative Floppy Iris Syndrome during cataract surgery. ( 5.2 ) Screen for the presence of prostate cancer prior to treatment for BPH and at regular intervals afterwards. ( 5.3 )

Strong cytochrome P450 (CYP) 3A inhibitors may increase exposure to doxazosin and increased risk of hypotension. ( 7.1 ) Concomitant administration of doxazosin mesylate with a phosphodiesterase-5 (PDE-5) inhibitor can result in additive blood pressure lowering effects and symptomatic hypotension. ( 7.2 )

8.1Pregnancy Risk Summary

The limited available data with doxazosin mesylate in pregnant women are not sufficient to inform a drug-associated risk for major birth defects and miscarriage. However, untreated hypertension during pregnancy can result in increased maternal risks [see Clinical Considerations ] . In animal reproduction studies, no adverse developmental effects were observed when doxazosin was orally administered to pregnant rabbits and rats during the period of organogenesis at doses of up to 41 and 20 mg/kg, respectively (exposures in rabbits and rats were 10 and 4 times, respectively, the human AUC exposures with a 12 mg/day therapeutic dose).

A dosage regimen of 82 mg/kg/day in the rabbit was associated with reduced fetal survival [see Data ]. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2–4% and 15–20%, respectively. Clinical Considerations Disease-associated maternal and/or embryo/fetal risk Hypertension in pregnancy increases the maternal risk for pre-eclampsia, gestational diabetes, premature delivery, and delivery complications (e.g., need for cesarean section, and post-partum hemorrhage).