Treatment of hypertension alone or in conjunction with diuretics, cardiac glycosides, ACE inhibitors, or calcium antagonists (particularly appropriate for those with hypertension and other cardiovascular risk factors such as hypercholesterolemia and diabetes mellitus); treatment of urinary outflow obstruction and/or obstructive and irritative symptoms associated with benign prostatic hyperplasia (BPH), particularly useful in patients with troublesome symptoms who are unable or unwilling to undergo invasive procedures, but who require rapid symptomatic relief; can be used in combination with finasteride
Doxazosin is in a group of drugs called alpha-adrenergic blockers. Doxazosin causes the blood vessels (veins and arteries) to relax and expand, improving blood flow. Doxazosin also relaxes muscles in the prostate and bladder neck, making it easier to urinate.
Doxazosin is used to treat hypertension (high blood pressure) and benign prostatic hyperplasia (enlarged prostate).
Doxazosin may also be used for purposes other than those listed in this medication guide.
Take this medication exactly as it was prescribed for you. Do not take the medication in larger amounts, or take it for longer than recommended by your doctor. Your doctor may occasionally change your dose to make sure you get the best results from this medication.
Take each dose with a full glass of water.
Doxazosin lowers blood pressure and may cause dizziness or fainting, especially when you first start taking it, or when you start taking it again. To avoid falling, take the first dose of doxazosin at bedtime. You may wish to continue taking this medication only at bedtime if it causes you to feel light-headed.
You may feel very dizzy when you first wake up. Be careful when standing or sitting up from a lying position.
If you stopped taking doxazosin for any reason and have started taking it again, you may feel especially dizzy or light-headed after your first few doses.
To be sure this medication is helping your condition, your blood pressure or prostate will need to be checked on a regular basis. It is important that you not miss any scheduled visits to your doctor.
If you are being treated for high blood pressure, keep using this medication even if you feel fine. High blood pressure often has no symptoms.
Store doxazosin at room temperature away from moisture and heat.
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have any of these serious side effects:
fast or pounding heartbeats; feeling light-headed, fainting; swelling in your hands, ankles, or feet; or penis erection that is painful or lasts 4 hours or longer.
Other, less serious side effects may be more likely to occur, such as:
weakness; headache; dizziness; or diarrhea, stomach pain.
Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome.
Doxazosin mesylate is a quinazoline compound that is a selective inhibitor of the alpha1 subtype of alpha adrenergic receptors. The chemical name of doxazosin mesylate is 1-(4-amino-6,7-dimethoxy- 2-quinazolinyl)-4-(1,4- benzodioxan-2-ylcarbonyl) piperazine methanesulfonate. The empirical formula for doxazosin mesylate is C23H25N5O5•CH4O3S and the molecular weight is 547.6. The inactive ingredients for all tablets are: microcrystalline cellulose, lactose, sodium starch glycolate, magnesium stearate and sodium lauryl sulfate. The 2 mg tablet contains FD&C yellow 10 and FD&C yellow 6; the 4 mg tablet contains FD&C yellow 6; the 8 mg tablet contains FD&C blue 10 and FD&C yellow 10.
Doxazosin has the following structural formula: