{"ok":true,"entry":{"slug":"doxazosin","kind":"medication","name":"doxazosin","aliases":["Cardura"],"brands_sg":["Cardura"],"class":"alpha-1 blocker","tags":["heart-bp"],"use_for":"high blood pressure and enlarged-prostate symptoms","use_after":"nhs: usually once a day, often for several years","use_duration":null,"take_with":"nhs: with a drink of water · alcohol adds side effects","pros":["sg label: usable as the first blood pressure agent","sg label: one drug covers bph and blood pressure","nhs: once a day, at the same time every day"],"cons":["nhs: headaches, dizziness and vertigo are common","nhs: ankle, foot and leg swelling is common","one sg brand only — cardura 2 mg tablets"],"dose_note":"the sg label for cardura states the hypertension ceiling as \"The full dosage range of doxazosin is 1 mg to 16 mg daily\" (usual dose 2–4 mg once daily), and for benign prostatic hyperplasia says the dose may be increased \"up to the maximum recommended dose of 8 mg\" — as directed on the label or by your doctor","dosage":null,"ul_status":null,"sg_class":"prescription-only","cautions":["orthostatic hypotension — nhs lists dizziness and light-headedness on standing as a reason it may not suit","an enlarged prostate together with low blood pressure, or with bladder or kidney problems — nhs","pregnancy — nhs: not usually used, as not enough is known about its safety","known hypersensitivity to quinazolines or doxazosin — ndf contraindication"],"clashes":[{"src":["nhs_doxazosin_int"],"note":"nhs lists them among medicines that may not mix well with doxazosin","with":"erectile dysfunction medicines such as sildenafil"},{"src":["nhs_doxazosin_int"],"note":"nhs lists this antibiotic among medicines that may not mix well with doxazosin","with":"clarithromycin"},{"src":["nhs_doxazosin_int"],"note":"nhs lists them among medicines that may not mix well with doxazosin","with":"other blood pressure medicines"},{"src":["nhs_doxazosin_int"],"note":"nhs lists both groups among medicines that may not mix well with doxazosin","with":"antifungal and hiv medicines"},{"src":["nhs_doxazosin_int"],"food":true,"note":"nhs: best not to drink alcohol, as this can raise the risks of side effects","with":"alcohol"}],"sources":[{"id":"hsa_register","url":"https://data.gov.sg/api/action/datastore_search?resource_id=d_767279312753558cbf19d48344577084&limit=6000","label":"HSA — Listing of Registered Therapeutic Products (data.gov.sg d_767279312753558cbf19d48344577084), Forensicclassification column; read from the cached copy at /tmp/hsa_all.json and filtered locally, not re-fetched","quote":"CARDURA TABLET 2 mg SIN05014P | DOXAZOSIN MESYLATE 2.43MG EQV DOXAZOSIN | Prescription Only | C02CA04 — the ONLY doxazosin row in the register","accessed":"2026-08-27"},{"id":"ndf_cardura","url":"https://www.ndf.gov.sg/about-drugs/product-information/sin05014p/","label":"MOH National Drug Formulary (Singapore) — CARDURA TABLET 2 MG [SIN05014P], product information","quote":"DOXAZOSIN MESYLATE 2.43 MG EQV DOXAZOSIN - 2 MG … Forensic Classification PRESCRIPTION ONLY MEDICINES … Anatomical Therapeutic Chemical (ATC) code C02CA04 … Prescription-only Medicines with Exemptions for Supply without Prescription NA","accessed":"2026-08-27"},{"id":"ndf_cardura_ind","url":"https://www.ndf.gov.sg/about-drugs/product-information/sin05014p/","label":"MOH National Drug Formulary (Singapore) — CARDURA [SIN05014P], section 4.1 Therapeutic indications","quote":"Doxazosin is indicated for the treatment of hypertension and can be used as the initial agent to control blood pressure in the majority of patients … also indicated for … symptoms associated with benign prostatic hyperplasia (BPH).","accessed":"2026-08-27"},{"id":"ndf_cardura_dose","url":"https://www.ndf.gov.sg/about-drugs/product-information/sin05014p/","label":"MOH National Drug Formulary (Singapore) — CARDURA [SIN05014P], section 4.2 Posology and method of administration","quote":"The full dosage range of doxazosin is 1 mg to 16 mg daily … The usual dose is 2 mg to 4 mg once daily … up to the maximum recommended dose of 8 mg.","accessed":"2026-08-27"},{"id":"ndf_cardura_ci","url":"https://www.ndf.gov.sg/about-drugs/product-information/sin05014p/","label":"MOH National Drug Formulary (Singapore) — CARDURA [SIN05014P], section 4.3 Contraindications","quote":"Doxazosin is contraindicated in patients with a known hypersensitivity to quinazolines, doxazosin, or any of the inert ingredients.","accessed":"2026-08-27"},{"id":"nhs_doxazosin","url":"https://www.nhs.uk/medicines/doxazosin/","label":"NHS medicines A–Z — Doxazosin, what it is for (page last reviewed 3 August 2026)","quote":"Doxazosin is used to: lower high blood pressure (hypertension) … treat the symptoms of an enlarged prostate, such as problems with peeing. Doxazosin is a type of medicine called an alpha blocker.","accessed":"2026-08-27"},{"id":"nhs_doxazosin_admin","url":"https://www.nhs.uk/medicines/doxazosin/","label":"NHS medicines A–Z — Doxazosin, how to take it","quote":"You'll usually need to take it once a day, at the same time every day, with a drink of water … Doxazosin treatment is often long term, and you'll probably need to take it for several years","accessed":"2026-08-27"},{"id":"nhs_doxazosin_se","url":"https://www.nhs.uk/medicines/doxazosin/","label":"NHS medicines A–Z — Doxazosin, side effects","quote":"Common side effects of doxazosin include: headaches, dizziness and feeling like everything around you is spinning (vertigo); swelling, usually in your ankles, feet and legs (oedema); cold-like symptoms … tummy pain; feeling sick (nausea) and being sick (vomiting)","accessed":"2026-08-27"},{"id":"nhs_doxazosin_who","url":"https://www.nhs.uk/medicines/doxazosin/","label":"NHS medicines A–Z — Doxazosin, who can and cannot take it","quote":"you have an enlarged prostate and low blood pressure; you have an enlarged prostate and bladder or kidney problems; you've been told you have orthostatic hypotension … not usually used during pregnancy as not enough is known about its safety.","accessed":"2026-08-27"},{"id":"nhs_doxazosin_int","url":"https://www.nhs.uk/medicines/doxazosin/","label":"NHS medicines A–Z — Doxazosin, taking it with other medicines, food and drink","quote":"medicines to treat erectile dysfunction, like sildenafil (Viagra); clarithromycin … some other blood pressure medicines; medicines to treat fungal infections; medicines to treat HIV … it's best not to drink alcohol while taking doxazosin","accessed":"2026-08-27"}],"brand_certs":null,"updated_at":"2026-08-29T16:16:18.585742+08:00"},"disclaimer":"kozen-x is not a medical device and does not give medical advice. it lists what published sources have written down. absence of a record is not the same as safe."}