Hypertension in CKD Pregnancy: Hypertension indication — as there are no adequate and well-controlled studies in pregnant women, safety during pregnancy has not been established; use only when, in the opinion of the physician, the potential benefit outweighs the potential risk. No teratogenic effects were seen in animal testing, but reduced foetal survival was observed in animals at extremely high doses. Breast-feeding: excretion in breast milk was demonstrated to be very low (relative infant dose less than 1%) but human data are very limited and a risk to the newborn or infant cannot be excluded — use only when the potential benefit outweighs the potential risk. For the benign prostatic hyperplasia indication this section is not applicable.

Doxazosin (Hypertension/BPH in CKD)

Brand names: Cardura

Doxazosin is an alpha-1 adrenoceptor blocker used for hypertension and for benign prostatic hyperplasia.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Hypertension: initial dose 1 mg once daily, to minimise the potential for postural hypotension and/or syncope. Dosage may then be increased to 2 mg after an additional one or two weeks of therapy and thereafter, if necessary, to 4 mg. The majority of patients who respond will do so at a dose of 4 mg or less. Dosage can be further increased if necessary to 8 mg or the maximum recommended dose of 16 mg.

Route: Oral

Frequency: Once daily — may be administered in the morning or the evening

Max: 16 mg once daily (hypertension); 8 mg once daily (benign prostatic hyperplasia)

Source: UK SPC (eMC) for CARDURA Tablet 2 mg, §4.2 (https://www.medicines.org.uk/emc/product/6957/smpc). This is the IMMEDIATE-RELEASE tablet SPC; no studies have been conducted with doxazosin prolonged-release formulations in respect of the PDE-5 inhibitor advice, and modified-release products have a different posology — check the specific product SPC. BENIGN PROSTATIC HYPERPLASIA: recommended initial dosage 1 mg once daily to minimise the potential for postural hypotension and/or syncope; depending on the individual patient's urodynamics and BPH symptomatology dosage may then be increased to 2 mg and thereafter to 4 mg and up to the maximum recommended dose of 8 mg. The recommended titration interval is 1-2 weeks and the usual recommended dose is 2-4 mg daily. ELDERLY: normal adult dosage. PAEDIATRIC: the safety and efficacy of Cardura in children and adolescents have NOT been established, so paedDose is null — verify any under-18 use against a children's formulary. HEPATIC IMPAIRMENT: there are only limited data in patients with liver impairment and on the effect of drugs known to influence hepatic metabolism (e.g. cimetidine); as with any drug wholly metabolised by the liver, administer with caution to patients with evidence of impaired liver function, and because there is no clinical experience in severe hepatic impairment use in those patients is NOT recommended. MONITORING: it is prudent medical practice to monitor blood pressure on initiation of therapy to minimise postural effects; the patient should be advised how to avoid symptoms of postural hypotension and cautioned to avoid situations where injury could result should dizziness or weakness occur. US labelling (cross-check, may differ from UK): monitor blood pressure for at least 6 hours following the initial dose and each dose increase, and if administration is discontinued for several days restart using the initial dosing regimen. NOTE ON SOURCES: eMC §4.5 was NOT captured in this bundle — the interaction entries below come from UK §4.4 plus §7 of the US label (Doxazosin tablets, Cardinal Health 107 LLC, label date 2026-04-24, https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=b2cb1c04-f7a7-4887-b41c-) and must be verified against the full SPC. §4.4 and the US §5/§6 sections were truncated at the source-fetch limit.

Dose adjustments

Renal

Since there is no change in pharmacokinetics in patients with impaired renal function, the usual adult dose of Cardura is recommended. Cardura is NOT dialysable. Note that doxazosin is contraindicated as monotherapy in patients with either overflow bladder or anuria with or without progressive renal insufficiency (§4.3).

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

• For the treatment of BPH: Initiate therapy at 1 mg once daily. Dose may be 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 ) 2.1 Dosing 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. 2.2 Benign Prostatic Hyperplasia The recommended initial dosage of doxazosin tablets is 1 mg given once daily either in …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2026-04-24. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Contraindications

Hypersensitivity to the active substance or other types of quinazolines (e.g. prazosin, terazosin, doxazosin), or to any of the excipients
Patients with a history of orthostatic hypotension
Patients with benign prostatic hyperplasia and concomitant congestion of the upper urinary tract, chronic urinary tract infection or bladder stones
Patients with hypotension (for the benign prostatic hyperplasia indication only)
Contraindicated as monotherapy in patients with either overflow bladder or anuria with or without progressive renal insufficiency

Side effects

Common: dizziness, headache, somnolence; hypotension and postural hypotension; palpitation, tachycardia
Common: asthenia, chest pain, influenza-like symptoms, peripheral oedema; back pain, myalgia; fatigue and malaise
Common: abdominal pain, dyspepsia, dry mouth, nausea; respiratory tract infection, urinary tract infection; bronchitis, cough, dyspnoea, rhinitis
Uncommon: syncope, hypoesthesia, tremor, cerebrovascular accident; angina pectoris, myocardial infarction; impotence; cystitis, urinary incontinence; abnormal liver function tests; agitation, depression, anxiety, insomnia, nervousness
Rare/very rare: bradycardia and cardiac arrhythmias; leukopenia, thrombocytopenia; cholestasis, hepatitis, jaundice; priapism and gynaecomastia; intraoperative floppy iris syndrome during cataract surgery (frequency not known)

Interactions

Phosphodiesterase-5 inhibitors (sildenafil, tadalafil, vardenafil) — concomitant administration should be done with caution as both drugs have vasodilating effects and may lead to symptomatic hypotension; initiate PDE-5 inhibitor treatment only if the patient is haemodynamically stabilised on alpha-blocker therapy, start at the lowest possible dose and respect a 6-hour interval from intake of doxazosin (UK §4.4)
Strong CYP3A inhibitors — doxazosin is a substrate of CYP3A4 in vitro and strong CYP3A inhibitors may increase exposure to doxazosin; monitor blood pressure and for symptoms of hypotension (US label §7.1)
Drugs known to influence hepatic metabolism (e.g. cimetidine) — only limited data are available (UK §4.2)
Other vasodilatory antihypertensive agents — caution is advised in patients with acute cardiac conditions (pulmonary oedema due to aortic or mitral stenosis, high-output cardiac failure, right-sided heart failure due to pulmonary embolism or pericardial effusion, left ventricular heart failure with low filling pressure) (UK §4.4)
eMC §4.5 was not captured in the source bundle and must be checked on the SPC

Clinical monograph

How it works

It blocks alpha-1 receptors, relaxing vascular smooth muscle to lower blood pressure and relaxing smooth muscle in the prostate and bladder neck to improve urinary flow.

Prescribing in practice

First-dose and postural hypotension can occur, so introduce treatment cautiously.
In the ALLHAT trial it was associated with worse heart-failure outcomes than a thiazide-type diuretic, so it is not a first-line antihypertensive.
A modified-release form is available and should be swallowed whole.

Monitoring

Monitor blood pressure, including lying and standing measurements, particularly at initiation and dose changes.

Counselling the patient

Stand up slowly, especially with the first dose, and take the first dose before going to bed if advised.
Report dizziness, fainting or palpitations.

Evidence & guidelines

ALLHAT showed worse heart-failure outcomes versus diuretic; reserved as add-on therapy for resistant hypertension in UK guidance (NICE NG136).

Reference: PATHWAY-2 Trial (Williams et al. Lancet 2015); NICE NG136 (Hypertension); NICE CG97 (BPH); SPC Cardura; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Drugs

Spironolactone (Resistant Hypertension in CKD) · Hypertension in CKD

Pathways