| name | Doxazosin (Cardura) |
| classification | Alpha-1 adrenergic receptor antagonist |
| pharmacokinetics | | absorption | Well absorbed orally, peak plasma concentration reached in 2-4 hours. | | distribution | Distributes widely throughout the body. | | metabolism | Metabolized primarily in the liver, predominantly by CYP3A4. | | excretion | Eliminated primarily in the urine as metabolites. |
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| suggested dosage | | initial | 1 mg orally once daily, titrated upward to 8 mg once daily as tolerated. | | notes | Patients should be monitored for blood pressure response and for adverse effects during titration. Adjustments should be made at appropriate intervals (usually 1-2 weeks). | | weight specific consideration | Dosage adjustments based solely on weight are not generally necessary, but should be adjusted as per clinical judgement for patients with significant hepatic or renal impairment. | | male patient 25 70kg | Initial dose of 1mg daily, titrated as tolerated. Following clinical assessment and blood pressure monitoring, the dose can increase as needed to a maximum of 8mg daily. |
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| indications | | 1 | Benign prostatic hyperplasia (BPH): Treatment of symptoms such as difficulty urinating, weak urinary stream, nocturia. | | 2 | Essential hypertension |
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| safety in pregnancy | Category C. There is limited data on the use of doxazosin in pregnant women. Use only if the potential benefit justifies the potential risk to the fetus. Consult a doctor if considering use in pregnancy. |
| safety in breastfeeding | It is not known whether doxazosin is excreted in breast milk. Use caution and consider the benefit versus risk of treatment if breastfeeding. |
| side effects | | 1 | Orthostatic hypotension (most common, especially initially): Dizziness, lightheadedness, fainting. | | 2 | Headache | | 3 | Nasal congestion | | 4 | Fatigue | | 5 | Drowsiness | | 6 | Ejaculatory dysfunction (reduced libido, impotence) | | 7 | edema | | 8 | Gastrointestinal upset | | 9 | Rash | | 10 | Myalgia | | 11 | Palpitations | | 12 | Syncope | | 13 | peripheral edema |
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| alternatives | |
| contraindications | | 1 | Hypersensitivity to doxazosin or other related drugs. | | 2 | Severe hepatic impairment. | | 3 | Severe uncontrolled hypotension. |
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| interactions | | 1 | Concurrent use with other antihypertensive medications may require dose adjustment. | | 2 | Alpha-blocker medications can increase the risk of orthostatic hypotension if taken with other medications that lower blood pressure. | | 3 | Grapefruit juice can increase the risk of side effects | | 4 | CYP3A4 inhibitors (e.g., ketoconazole, erythromycin) may increase plasma levels of doxazosin, requiring dose adjustment. |
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| warnings and precautions | | 1 | Caution in patients with a history of cardiac or hepatic disease or peripheral vascular disease. | | 2 | Monitor blood pressure closely, especially when initiating or adjusting the dose. | | 3 | Monitor for orthostatic hypotension, particularly during the first few days of treatment, and in patients with dehydration. | | 4 | Avoid driving or operating machinery until the patient's response to the medication is known, and monitor for syncope. | | 5 | Be cautious in patients taking other medications that may decrease blood pressure. |
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| additional information | | 1 | Doxazosin should be taken at the same time each day. | | 2 | Do not discontinue the medication abruptly, as this may lead to rebound hypertension. |
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| patient profile | |
