Doxazosin 1 mg Tablet, 100-count
Other active recalls for Doxazosin (different manufacturers) — 1 · tap to view
🆔 Identity & classification
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🏷️ RxNorm drug class
This medicine belongs to the alpha-Adrenergic Blocker class.
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🏭 Manufacturer & labeler
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🩺 Clinical
Doxazosin is used to: treat benign prostatic hyperplasia (BPH; enlarged prostate that can cause difficulty urinating, painful urination or increased urinary frequency or urgency). treat high blood pressure. Doxazosin is in a class of medications called alpha-blockers. It relieves the symptoms of BPH by relaxing the muscles of the bladder and prostate to allow urine to flow more easily. It lowers blood pressure by relaxing the blood vessels so that blood can flow more easily through the body.
Read the full MedlinePlus article ↗- Doxazosin tablets are used for two main things: relieving the urinary symptoms of an enlarged prostate (BPH) — things like a weak stream, frequent urges to urinate, or waking up at...
- Yes, that's actually one of the most common things people notice, especially with the first dose or after a dose increase. Doxazosin can cause your blood pressure to drop when you...
- I felt really dizzy after my first dose — is that normal?
- For regular doxazosin tablets, you can take them either in the morning or the evening — just pick a consistent time and stick with it. If you're taking Cardura XL (the extended-rel...
Patient education
Supplement & herbal interactions
Some supplements/herbs that may interact with Doxazosin Mesylate — tap one for details:
Doxazosin Mesylate may be associated with lower levels of 1 nutrient — worth a chat with your pharmacist, not a cause for alarm.
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Ask a licensed pharmacist directly — free, answered by our team.
💊 What it looks like
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🧪 Inactive Ingredients / Excipients
Inactive ingredients, also called excipients, are components of the drug product other than the active ingredient. They may include fillers, dyes, coatings, preservatives, flavors, or other formulation ingredients.
💡 Tap an ingredient (hover on desktop) to see what it is and why it’s used.
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UNII EWQ57Q8I5X
Lactose monohydrate is a natural sugar derived from milk. It serves as a filler and binder in tablets and capsules, helping create the proper size, texture, and consistency of the medicine.
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UNII 70097M6I30
Magnesium stearate is a salt made from magnesium and stearic acid, a fatty substance. It's used in tablets and capsules as a lubricant and glidant to help ingredients flow smoothly during manufacturing and prevent sticking.
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UNII PNR0YF693Y
A plant-based powder made from purified wood cellulose. It acts as a filler to add bulk, a binder to hold ingredients together, and a disintegrant to help the tablet break apart in the stomach.
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UNII ETJ7Z6XBU4
Silicon dioxide is a naturally occurring mineral used as a glidant and anti-caking agent. It helps powder ingredients flow smoothly and prevents clumping during manufacturing and storage.
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UNII 368GB5141J
A detergent and foaming agent derived from coconut or palm oil. In medications, it helps break down and mix oil and water-based ingredients, aids in tablet disintegration, and improves how the drug dissolves and spreads in the mouth or digestive system.
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UNII H8AV0SQX4D
A modified starch derived from potato or corn starch. It absorbs water quickly and helps tablets or capsules break apart and dissolve in the stomach, acting as a disintegrant to ensure the medicine releases its active ingredients properly.
6 inactive ingredients listed in the exact product block matched to this NDC.
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ingredient classCode="IACT" elements from the exact product block matched by this NDC. Label-section narrative from DailyMed / the openFDA label index is shown separately when available.Inactive ingredient FAQ
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💲 Pricing
A drug doesn't have one price. Each row is a different public payment system, and none is what you'd pay at the counter — that depends on your insurance. The ⓘ on each row explains what it measures.
| Price system | Per ea | Per package |
|---|---|---|
| Retail pharmacies payNADAC · weekly | $0.077 | $7.73 / 100 tablets |
| Medicaid paysCMS SDUD · 12 mo | $0.2365 | $23.65 / 100 tablets |
| Medicare drug plans payPart D · Q2 2026 | $0.1425 | $14.25 / 100 tablets |
Where does this data come from?
🔁 Therapeutic equivalents
| Product | Labeler | Pack | NADAC/unit | TE | Status | Price vs. this |
|---|---|---|---|---|---|---|
| Doxazosin 1 mg 00093-2070-01 | Teva | 100 tablets | $0.077 | AB | Availability likely | — |
| Doxazosin 1 mg 00832-0356-11 | Upsher-Smith | 100 tablets | $0.077 | AB | Availability likely | — |
| Doxazosin 1 mg 00904-5522-61 | Major | 100 tablets | $0.077 | AB | Availability likely | — |
| Doxazosin 1 mgthis 16571-0165-01 | Rising | 100 tablets | $0.077 | AB | Availability likely | — |
| Doxazosin 1 mg 23155-0092-01 | Heritage | 100 tablets | $0.077 | AB | Availability likely | — |
| Doxazosin Mesylate 1 mg 29300-0351-01 | Unichem | 100 tablets | $0.077 | AB | Availability likely | — |
| Doxazosin 1 mg 50268-0222-15 | AvPAK | 50 tablets | $0.077 | AB | Availability likely | — |
| Doxazosin 1 mg 59651-0892-01 | Aurobindo | 100 tablets | $0.077 | AB | Availability likely | — |
| Doxazosin mesylate 1 mg 59762-1388-07 | Mylan | 100 tablets | $0.077 | AB | Availability likely | — |
| Doxazosin 1 mg 60505-0093-00 | Apotex | 100 tablets | $0.077 | AB | Availability likely | — |
| Doxazosin mesylate 1 mg 62135-0051-90 | Chartwell | 90 tablets | $0.077 | — | Availability likely | — |
| Doxazosin 1 mg 68084-0836-01 | American | 100 tablets | $0.077 | AB | Availability likely | — |
| Doxazosin 1 mg 68382-0783-01 | Zydus | 100 tablets | $0.077 | AB | Availability likely | — |
| Doxazosin 1 mg 16729-0211-01 | Accord | 100 tablets | $0.078 | AB | Availability likely | +1% |
| Doxazosin 1 mg 50090-0701-00 | A-S | 30 tablets | — | AB | FDA listed | — |
| Doxazosin 1 mg 50090-2153-00 | A-S | 30 tablets | — | AB | FDA listed | — |
| Doxazosin 1 mg 51655-0476-52 | Northwind | 30 tablets | — | AB | FDA listed | — |
| Cardura 1 mg 58151-0074-01 | Viatris | 100 tablets | — | AB | FDA listed | — |
| Doxazosin 1 mg 63629-7891-01 | Bryant | 30 tablets | — | AB | FDA listed | — |
| Doxazosin 1 mg 68071-4272-03 | NuCare | 30 tablets | — | AB | FDA listed | — |
| Doxazosin 1 mg 70771-1112-00 | Zydus | 1000 tablets | — | AB | FDA listed | — |
| Doxazosin 1 mg 71335-2803-01 | Bryant | 30 tablets | — | AB | FDA listed | — |
| Doxazosin 1 mg 84677-0044-01 | Golden | 100 tablets | — | AB | FDA listed | — |
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⏳ Availability & generic status
This product is an FDA-approved generic. Other versions of the same drug are listed under Therapeutic equivalents, least expensive first.
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🗺️ Medicaid utilization & spend
🔬 Reported adverse events (FAERS)
Top reported reactions
Reporter sex
Serious outcomes
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📦 Packaging — all sizes for this product
| Package NDC | Description | Marketing start | Status |
|---|---|---|---|
| 16571-0165-01 You're viewing this | 100 TABLET in 1 BOTTLE (16571-165-01) | 2024-05-20 | Active |
📄 Full prescribing information FDA SPL
🎯 Indications and Usage ▾
1 INDICATIONS AND USAGE Doxazosin tablets are an alpha 1 adrenergic antagonist indicated for: Signs and symptoms of Benign Prostatic Hyperplasia (BPH) Treatment of Hypertension
1.1Benign Prostatic Hyperplasia (BPH) Doxazosin tablets are indicated for the treatment of the signs and symptoms of BPH.
1.2Hypertension Doxazosin tablets are indicated for the treatment of hypertension, to lower blood pressure. Lowering blood pressure reduces the risk of fatal and nonfatal cardiovascular events, primarily strokes and myocardial infarctions. These benefits have been seen in controlled trials of antihypertensive drugs from a wide variety of pharmacologic classes, including this drug.
Control of high blood pressure should be part of comprehensive cardiovascular risk management, including, as appropriate, lipid control, diabetes management, antithrombotic therapy, smoking cessation, exercise, and limited sodium intake. Many patients will require more than one drug to achieve blood pressure goals. For specific advice on goals and management, see published guidelines, such as those of the National High Blood Pressure Education Program's Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC).
Numerous antihypertensive drugs, from a variety of pharmacologic classes and with different mechanisms of action, have been shown in randomized controlled trials to reduce cardiovascular morbidity and mortality, and it can be concluded that it is blood pressure reduction, and not some other pharmacologic property of the drugs, that is largely responsible for those benefits. The largest and most consistent cardiovascular outcome benefit has been a reduction in the risk of stroke, but reductions in myocardial infarction and cardiovascular mortality also have been seen regularly.
Elevated systolic or diastolic pressure causes increased cardiovascular risk, and the absolute risk increase per mmHg is greater at higher blood pressures, so that even modest reductions of severe hypertension can provide substantial benefit. Relative risk reduction from blood pressure reduction is similar across populations with varying absolute risk, so the absolute benefit is greater in patients who are at higher risk independent of their hypertension (for example, patients with diabetes or hyperlipidemia), and such patients would be expected to benefit from more aggressive treatment to a lower blood pressure goal.
Some antihypertensive drugs have smaller blood pressure effects (as monotherapy) in black patients, and many antihypertensive drugs have additional approved indications and effects (e.g., on angina, heart failure, or diabetic kidney disease). These considerations may guide selection of therapy. Doxazosin tablets may be used alone or in combination with other antihypertensives.
⏱️ Dosage and Administration ▾
2 DOSAGE AND ADMINISTRATION For the treatment of BPH: Initiate therapy at 1 mg once daily. Dose maybe titrated at 1 to 2-week intervals, up to 8 mg once daily. ( 2.2 ) For the treatment hypertension: Initiate therapy at 1 mg once daily. Dose may be titrated as needed, up to 16 mg once daily. ( 2.3 )
2.1Dosing Information Following the initial dose and with each dose increase of doxazosin tablets, monitor blood pressure for at least 6 hours following administration. If doxazosin tablets administration is discontinued for several days, therapy should be restarted using the initial dosing regimen.
2.2Benign Prostatic Hyperplasia The recommended initial dosage of doxazosin tablets are 1 mg given once daily either in the morning or evening. Depending on the individual patient's urodynamics and BPH symptomatology, the dose may be titrated at 1 to 2 week intervals to 2 mg, and thereafter to 4 mg and 8 mg once daily. The maximum recommended dose for BPH is 8 mg once daily. Routinely monitor blood pressure in these patients.
2.3Hypertension The initial dosage of doxazosin tablets is 1 mg given once daily. Daily dosage may be doubled up 16 mg once daily, as needed, to achieve the desired reduction in blood pressure.
💊 Dosage Forms and Strengths ▾
3 DOSAGE FORMS AND STRENGTHS Doxazosin Tablets, USP are available containing doxazosin mesylate, USP equivalent to 1 mg, 2 mg, 4 mg or 8 mg of doxazosin. The 1 mg tablets are White to off white, capsule shaped, debossed 'D' '1' on one side and break line on other side. The 2 mg tablets are White to off white, capsule shaped, debossed 'D' '2' on one side and break line on other side.
The 4 mg tablets are White to off white, capsule shaped, debossed 'D' '4' on one side and break line on other side. The 8 mg tablets are White to off white, capsule shaped, debossed 'D' '8' on one side and break line on other side. Tablets: 1 mg, 2 mg, 4 mg, 8 mg.
⛔ Contraindications ▾
4 CONTRAINDICATIONS The use of doxazosin tablets are 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 tablets. ( 4 )
⚠️ Warnings and Cautions ▾
5 WARNINGS AND PRECAUTIONS 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 )
5.1Postural Hypotension Postural hypotension with or without symptoms (e.g., dizziness) may develop within a few hours following administration of doxazosin tablets. However, infrequently, symptomatic postural hypotension has also been reported later than a few hours after dosing. As with other alpha-blockers, there is a potential for syncope, especially after the initial dose or after an increase in dosage strength.
Advise patient how to avoid symptoms resulting from postural hypotension and what measures to take should they develop. Concomitant administration of doxazosin tablets with a PDE-5 inhibitor can result in additive blood pressure lowering effects and symptomatic hypotension.
5.2Cataract Surgery Intraoperative Floppy Iris Syndrome (IFIS) has been observed during cataract surgery in some patients on or previously treated with alpha 1 blockers. This variant of small pupil syndrome is characterized by the combination of a flaccid iris that billows in response to intraoperative irrigation currents, progressive intraoperative miosis despite preoperative dilation with standard mydriatic drugs, and potential prolapse of the iris toward the phacoemulsification incisions. The patient's surgeon should be prepared for possible modifications to their surgical technique, such as the utilization of iris hooks, iris dilator rings, or viscoelastic substances.
There does not appear to be a benefit of stopping alpha 1 blocker therapy prior to cataract surgery.
5.3Prostate Cancer Carcinoma of the prostate causes many of the symptoms associated with BPH and the two disorders frequently co-exist. Carcinoma of the prostate should therefore be ruled out prior to commencing therapy with doxazosin tablets for the treatment of BPH.
5.4Priapism Alpha 1 antagonists, including doxazosin, have been associated with priapism (painful penile erection, sustained for hours and unrelieved by sexual intercourse or masturbation). This condition can lead to permanent impotence if not promptly treated.
🤒 Adverse Reactions ▾
6 ADVERSE REACTIONS The most commonly reported adverse reactions from clinical trials are Fatigue, malaise, hypotension, and dizziness. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Rising Pharma Holdings, Inc. at 1-844-874-7464 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.
6.1Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Benign Prostatic Hyperplasia (BPH) The incidence of adverse events has been ascertained from worldwide clinical trials in 965 BPH patients. The incidence rates presented below (Table 2) are based on combined data from seven placebo-controlled trials involving once-daily administration of doxazosin tablets in doses of 1 to 16 mg in hypertensives and 0.5 to 8 mg in normotensives.
Adverse reactions occurring more than 1% more frequently in BPH patients treated with doxazosin tablets vs placebo are summarized in Table 1. Table 1. Adverse Reactions Occurring more than 1% More Frequently in BPH Patients Treated with Doxazosin tablets Versus Placebo BODY SYSTEM Doxazosin Tablets N = 665 Placebo N = 300 NERVOUS SYSTEM DISORDERS Dizziness Includes vertigo 15.6% 9.0% Somnolence 3.0% 1.0% CARDIAC DISORDERS Hypotension 1.7% 0% RESPIRATORY, THORACIC AND MEDIASTINAL DISORDERS Dyspnoea 2.6% 0.3% GASTROINTESTINAL DISORDERS Dry Mouth 1.4% 0.3% GENERAL DISORDERS AND ADMINISTRATION SITE CONDITIONS Fatigue 8.0% 1.7% Oedema 2.7% 0.7% Other adverse reactions occurring less than 1% more frequently in BPH patients treated with doxazosin tablets vs placebo but plausibly related to doxazosin tablets include: palpitations.
Hypertension Doxazosin tablets has been administered to approximately 4000 hypertensive patients in clinical trials, of whom 1679 were included in the hypertension clinical development program. In placebo-controlled studies, adverse events occurred in 49% and 40% of patients in the doxazosin and placebo groups, respectively, and led to discontinuation in 2% of patients in each group. Adverse reactions occurring more than 1% more frequently in hypertensive patients treated with doxazosin tablets vs placebo are summarized in Table 1.
Postural effects and edema appeared to be dose-related. The prevalence rates presented below are based on combined data from placebo-controlled studies involving once-daily administration of doxazosin at doses ranging from 1 to 16 mg. Table 2.
Adverse Reactions Occurring more than 1% More Frequently in Hypertensive Patients Treated with Doxazosin tablets versus Placebo BODY SYSTEM Doxazosin Tablets N = 339 Placebo N = 336 NERVOUS SYSTEM DISORDERS Dizziness 19% 9% Somnolence 5% 1% RESPIRATORY, THORACIC AND MEDIASTINAL DISORDERS Rhinitis 3% 1% RENAL AND URINARY DISORDERS Polyuria 2% 0% REPRODUCTIVE SYSTEM AND BREAST DISORDERS GENERAL DISORDERS AND ADMINISTRATION SITE CONDITIONS Fatigue / Malaise 12% 6% Other adverse reactions occurring less than 1% more frequently in hypertensive patients treated with doxazosin tablets vs placebo but plausibly related to doxazosin tablets use include vertigo, hypotension, hot flushes, epistaxis and oedema.
Doxazosin tablets has been associated with decreases in white blood cell counts. Laboratory changes observed in clinical studies Leukopenia/Neutropenia: Decreases in mean white blood cell (WBC) and mean neutrophil count were observed in controlled clinical trials of hypertensive patients receiving doxazosin tablets. In cases where follow-up was available, WBC and neutrophil counts returned to normal after discontinuation of doxazosin tablets.
No patients became symptomatic as a result of the low WBC or neutrophil counts.
6.2Postmarketing Experience The following adverse reactions have been identified during post-approval use of doxazosin tablets. Because these reactions are reported voluntarily from a…
🔄 Drug Interactions ▾
7 DRUG INTERACTIONS Strong cytochrome P450 (CYP) 3A inhibitors may increase exposure to doxazosin and increased risk of hypotension ( 7.1 ) Concomitant administration of doxazosin tablets with a phosphodiesterase-5 (PDE-5) inhibitor can result in additive blood pressure lowering effects and symptomatic hypotension. ( 7.2 )
7.1CYP 3A Inhibitors In vitro studies suggest that doxazosin is a substrate of CYP 3A4. Strong CYP3A inhibitors may increase exposure to doxazosin. Monitor blood pressure and for symptoms of hypotension when doxazosin tablets are used concomitantly with strong CYP3A inhibitors [see Clinical Pharmacology ( 12.3 )].
7.2Phosphodiesterase-5 (PDE-5) inhibitors Concomitant administration of doxazosin tablets with a phosphodiesterase-5 (PDE-5) inhibitor can result in additive blood pressure lowering effects and symptomatic hypotension. Monitor blood pressure and for symptoms of hypotension [see Warnings and Precautions ( 5.1 )].
👥 Use in Specific Populations ▾
8 USE IN SPECIFIC POPULATIONS Hepatic Impairment: Monitor for hypotension. ( 8.6 , 12.3 )
8.1Pregnancy Risk Summary The limited available data with doxazosin tablets 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). Hypertension increases the fetal risk for intrauterine growth restriction and intrauterine death. Data Animal Data Radioactivity was found to cross the placenta following oral administration of labelled doxazosin to pregnant rats.
Studies in pregnant rabbits and rats at daily oral doses of up to 41 and 20 mg/kg, respectively (plasma drug concentrations of 10 and 4 times, respectively, the human AUC exposures with a 12 mg/day therapeutic dose), have revealed no evidence of adverse developmental effects. A dosage regimen of 82 mg/kg/day in the rabbit was associated with reduced fetal survival. In peri- and postnatal studies in rats, postnatal development at maternal doses of 40 or 50 mg/kg/day of doxazosin (about 8 times human AUC exposure with a 12 mg/day therapeutic dose) was delayed, as evidenced by slower body weight gain and slightly later appearance of anatomical features and reflexes.
8.2Lactation Risk Summary There is limited information on the presence of doxazosin tablets in human milk [see Data]. There is no information on the effects of doxazosin tablets on the breastfeed infant or the effects on milk production. Data A single case study reports that doxazosin tablets are present in human milk, which resulted in an infant dose of less than 1% of the maternal weight-adjusted dosage and a milk/plasma ratio of 0.1.
However, these data are insufficient to confirm the presence of doxazosin tablets in human milk.
8.4Pediatric Use The safety and effectiveness of doxazosin tablets have not been established in children.
8.5Geriatric Use Benign Prostatic Hyperplasia (BPH) The safety and effectiveness profile of doxazosin tablets was similar in the elderly (age ≥ 65 years) and younger (age < 65 years) patients. Hypertension Clinical studies of doxazosin tablets did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients.
In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal or cardiac function, and of concomitant disease or other drug therapy.
8.6Hepatic Impairment Doxazosin tablets are extensively metabolized in the liver. Hepatic impairment is expected to increase exposure to doxazosin. Use of doxazosin tablets in patients with severe hepatic impairment (Child-Pugh Class C) is not recommended. Monitor blood pr…
🤰 Pregnancy ▾
8.1Pregnancy Risk Summary The limited available data with doxazosin tablets 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). Hypertension increases the fetal risk for intrauterine growth restriction and intrauterine death. Data Animal Data Radioactivity was found to cross the placenta following oral administration of labelled doxazosin to pregnant rats.
Studies in pregnant rabbits and rats at daily oral doses of up to 41 and 20 mg/kg, respectively (plasma drug concentrations of 10 and 4 times, respectively, the human AUC exposures with a 12 mg/day therapeutic dose), have revealed no evidence of adverse developmental effects. A dosage regimen of 82 mg/kg/day in the rabbit was associated with reduced fetal survival. In peri- and postnatal studies in rats, postnatal development at maternal doses of 40 or 50 mg/kg/day of doxazosin (about 8 times human AUC exposure with a 12 mg/day therapeutic dose) was delayed, as evidenced by slower body weight gain and slightly later appearance of anatomical features and reflexes.
🧒 Pediatric Use ▾
8.4Pediatric Use The safety and effectiveness of doxazosin tablets have not been established in children.
🧓 Geriatric Use ▾
8.5Geriatric Use Benign Prostatic Hyperplasia (BPH) The safety and effectiveness profile of doxazosin tablets was similar in the elderly (age ≥ 65 years) and younger (age < 65 years) patients. Hypertension Clinical studies of doxazosin tablets did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients.
In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal or cardiac function, and of concomitant disease or other drug therapy.
🆘 Overdosage ▾
10 OVERDOSAGE Experience with doxazosin tablets overdosage is limited. Two adolescents, who each intentionally ingested 40 mg doxazosin tablets with diclofenac or acetaminophen, were treated with gastric lavage with activated charcoal and made full recoveries. A two-year-old child who accidently ingested 4 mg doxazosin tablets was treated with gastric lavage and remained normotensive during the five-hour emergency room observation period.
A six-month-old child accidentally received a crushed 1 mg tablet of doxazosin tablets and was reported to have been drowsy. A 32-year-old female with chronic renal failure, epilepsy, and depression intentionally ingested 60 mg doxazosin tablets (blood level = 0.9 mcg/mL; normal values in hypertensives = 0.02 mcg/mL); death was attributed to a grand mal seizure resulting from hypotension. A 39-year-old female who ingested 70 mg doxazosin tablets, alcohol, and Dalmane ® (flurazepam) developed hypotension which responded to fluid therapy.
The oral LD 50 of doxazosin is greater than 1000 mg/kg in mice and rats. The most likely manifestation of overdosage would be hypotension, for which the usual treatment would be intravenous infusion of fluid. As doxazosin is highly protein bound, dialysis would not be indicated.
🧬 Clinical Pharmacology ▾
12 CLINICAL PHARMACOLOGY
12.1Mechanism of Action Benign Prostatic Hyperplasia (BPH) The symptoms associated with benign prostatic hyperplasia (BPH), such as urinary frequency, nocturia, weak stream, hesitancy, and incomplete emptying are related to two components, anatomical (static) and functional (dynamic). The static component is related to an increase in prostate size caused, in part, by a proliferation of smooth muscle cells in the prostatic stroma. However, the severity of BPH symptoms and the degree of urethral obstruction do not correlate well with the size of the prostate.
The dynamic component of BPH is associated with an increase in smooth muscle tone in the prostate and bladder neck. The degree of tone in this area is mediated by the alpha l adrenoceptor, which is present in high density in the prostatic stroma, prostatic capsule and bladder neck. Blockade of the alpha 1 receptor decreases urethral resistance and may relieve the obstruction and BPH symptoms and improve urine flow.
Hypertension The mechanism of action of doxazosin tablets are selective blockade of the alpha 1 (postjunctional) subtype of adrenergic receptors. Studies in normal human subjects have shown that doxazosin competitively antagonized the pressor effects of phenylephrine (an alpha 1 agonist) and the systolic pressor effect of norepinephrine. Doxazosin and prazosin have similar abilities to antagonize phenylephrine.
The antihypertensive effect of doxazosin tablets results from a decrease in systemic vascular resistance. The parent compound doxazosin is primarily responsible for the antihypertensive activity. The low plasma concentrations of known active and inactive metabolites of doxazosin (2-piperazinyl, 6'- and 7'-hydroxy and 6- and 7-O-desmethyl compounds) compared to parent drug indicate that the contribution of even the most potent compound (6'-hydroxy) to the antihypertensive effect of doxazosin in man is probably small.
The 6'- and 7'-hydroxy metabolites have demonstrated antioxidant properties at concentrations of 5 µM , in vitro .
12.2Pharmacodynamics Benign Prostatic Hyperplasia (BPH) Administration of doxazosin tablets to patients with symptomatic BPH resulted in a statistically significant improvement in maximum urinary flow rate [see Clinical Studies ( 14.1 )]. Effect on Normotensive Patients with Benign Prostatic Hyperplasia (BPH) Although blockade of alpha 1 adrenoceptors also lowers blood pressure in hypertensive patients with increased peripheral vascular resistance, doxazosin tablets treatment of normotensive men with BPH did not result in a clinically significant blood pressure lowering effect (Table 4).
The proportion of normotensive patients with a sitting systolic blood pressure less than 90 mmHg and/or diastolic blood pressure less than 60 mmHg at any time during treatment with doxazosin tablets 1 - 8 mg once daily was 6.7% with doxazosin and not significantly different (statistically) from that with placebo (5%). Hypertension Administration of doxazosin tablets results in a reduction in systemic vascular resistance. In patients with hypertension, there is little change in cardiac output.
Maximum reductions in blood pressure usually occur 2 - 6 hours after dosing and are associated with a small increase in standing heart rate. Like other alpha 1 -adrenergic blocking agents, doxazosin has a greater effect on blood pressure and heart rate in the standing position.
12.3Pharmacokinetics Absorption After oral administration of therapeutic doses, peak plasma levels of doxazosin tablets occur at about 2 - 3 hours. Bioavailability is approximately 65%, reflecting first-pass metabolism of doxazosin by the liver. The effect of food on the pharmacokinetics of doxazosin tablets was examined in a crossover study with twelve hypertensive subjects.
Reductions of 18% in mean maximum plasma concentration (C max ) and 12% in the area under the concentration-time curve (AUC) occurred when doxazosin tablets were administered with food.…
🧬 Mechanism of Action ▾
12.1Mechanism of Action Benign Prostatic Hyperplasia (BPH) The symptoms associated with benign prostatic hyperplasia (BPH), such as urinary frequency, nocturia, weak stream, hesitancy, and incomplete emptying are related to two components, anatomical (static) and functional (dynamic). The static component is related to an increase in prostate size caused, in part, by a proliferation of smooth muscle cells in the prostatic stroma. However, the severity of BPH symptoms and the degree of urethral obstruction do not correlate well with the size of the prostate.
The dynamic component of BPH is associated with an increase in smooth muscle tone in the prostate and bladder neck. The degree of tone in this area is mediated by the alpha l adrenoceptor, which is present in high density in the prostatic stroma, prostatic capsule and bladder neck. Blockade of the alpha 1 receptor decreases urethral resistance and may relieve the obstruction and BPH symptoms and improve urine flow.
Hypertension The mechanism of action of doxazosin tablets are selective blockade of the alpha 1 (postjunctional) subtype of adrenergic receptors. Studies in normal human subjects have shown that doxazosin competitively antagonized the pressor effects of phenylephrine (an alpha 1 agonist) and the systolic pressor effect of norepinephrine. Doxazosin and prazosin have similar abilities to antagonize phenylephrine.
The antihypertensive effect of doxazosin tablets results from a decrease in systemic vascular resistance. The parent compound doxazosin is primarily responsible for the antihypertensive activity. The low plasma concentrations of known active and inactive metabolites of doxazosin (2-piperazinyl, 6'- and 7'-hydroxy and 6- and 7-O-desmethyl compounds) compared to parent drug indicate that the contribution of even the most potent compound (6'-hydroxy) to the antihypertensive effect of doxazosin in man is probably small.
The 6'- and 7'-hydroxy metabolites have demonstrated antioxidant properties at concentrations of 5 µM , in vitro .
📦 How Supplied / Storage and Handling ▾
16 HOW SUPPLIED/STORAGE AND HANDLING Doxazosin Tablets, USP are available as scored tablets for oral administration. Each tablet contains doxazosin mesylate, USP equivalent to 1 mg (white), 2 mg (white), 4 mg (white) or 8 mg (white) of the active constituent, doxazosin. The 1 mg tablets are White to off white, capsule shaped, debossed 'D' '1' on one side and break line on other side.
They are supplied as follows: Bottles of 100 tablets NDC 16571- 165-01 The 2 mg tablets are White to off white, capsule shaped, debossed 'D' '2' on one side and break line on other side. They are supplied as follows: Bottles of 100 tablets NDC 16571- 166-01 The 4 mg tablets are White to off white, capsule shaped, debossed 'D' '4' on one side and break line on other side. They are supplied as follows: Bottles of 100 tablets NDC 16571- 167-01 The 8 mg tablets are White to off white, capsule shaped, debossed 'D' '8' on one side and break line on other side.
They are supplied as follows: Bottles of 100 tablets NDC 16571- 168-01 Recommended Storage: Store at 25°C (77°F); excursions permitted to 15°C to 30°C (59°F to 86°F) [see USP Controlled Room Temperature]. Preserve in tight containers.
📋 Description ▾
11 DESCRIPTION Doxazosin mesylate, USP is a quinazoline compound that is a selective inhibitor of the alpha 1 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 C 23 H 25 N 5 O 5 • CH 4 O 3 S and the molecular weight is 547.58.
It has the following structure: Doxazosin mesylate, USP is freely soluble in formic acid, very slightly soluble in water and Methanol. Doxazosin tablets are available as colored tablets for oral use and contains 1 mg (white), 2 mg (white), 4 mg (white) and 8 mg (white) of doxazosin as the free base. The inactive ingredients for all tablets are: lactose monohydrate, microcrystalline cellulose, sodium starch glycolate, sodium lauryl sulfate, Colloidal Silicon dioxide and magnesium stearate. doxazocin-structure.jpg
💬 Information for Patients ▾
17 PATIENT COUNSELING INFORMATION Advise the patient to read the FDA-approved patient labeling (Patient Information). Postural Hypotension Advise patients of the possibility of syncopal and orthostatic symptoms, especially at the initiation of therapy, and urged to avoid driving or hazardous tasks for 24 hours after the first dose, after a dosage increase, and after interruption of therapy when treatment is resumed. Advise patients to report symptoms to their healthcare provider.
Priapism Advise patients of the possibility of priapism and to seek immediate medical attention if symptoms occur. Manufactured for: Rising Pharma Holdings, Inc. East Brunswick, NJ 08816 Made in India Code No.
DRUGS/TS/23/2007 Issued : 04/2024 PIR16801-00