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Hypertension in CKD Pregnancy: Avoid — teratogenicity risk based on animal studies; limited human data

Doxazosin (Hypertension/BPH in CKD)

Brand names: Cardura

Adult dose

Dose: Hypertension: 1 mg once daily; titrate to 4-8 mg OD (max 16 mg). BPH: 1-2 mg once daily; titrate to 4-8 mg OD.
Route: Oral
Frequency: Once daily (standard-release or modified-release XL)
Max: 16 mg/day (hypertension); 8 mg/day (BPH)
Alpha-1 adrenergic blocker. Preferred add-on antihypertensive in CKD — no dose adjustment required, not renally cleared. Useful dual action in male CKD patients with co-existing BPH. Start low (1 mg) — first-dose hypotension risk especially in elderly.

Paediatric dose

Route: Oral
Seek specialist opinion — not licensed in children for hypertension

Dose adjustments

Renal

No dose adjustment required — extensively hepatically metabolised; safe across all eGFR ranges including dialysis patients

Hepatic

Use with caution in moderate-severe hepatic impairment — reduced first-pass metabolism increases bioavailability

Clinical pearls

  • PATHWAY-2 trial: doxazosin was the comparator arm to spironolactone for resistant hypertension — spironolactone superior. However, doxazosin effective as 4th-line agent when spironolactone not tolerated or contraindicated (eGFR <45, hyperK risk).
  • Intraoperative Floppy Iris Syndrome (IFIS): alpha-1A blockade causes intraoperative iris prolapse during cataract surgery. Alpha-1A selectivity of tamsulosin means higher IFIS risk than doxazosin. Always inform ophthalmologist of current or past alpha-blocker use — even months/years prior.
  • First-dose hypotension: take first dose (1 mg) at bedtime to avoid symptomatic hypotension. Warn patients about dizziness on standing. Elderly CKD patients are particularly vulnerable.
  • XL formulation (Cardura XL): modified-release doxazosin — GITS technology. More consistent plasma levels, lower Cmax, fewer hypotensive episodes vs standard-release. Preferred for once-daily adherence. Do not crush or chew.
  • Renally safe: completely hepatically metabolised — no dose adjustment in any stage of CKD including haemodialysis patients. This makes it practically useful in advanced CKD where many antihypertensives require dose adjustments.

Contraindications

  • History of orthostatic hypotension
  • Concomitant phosphodiesterase-5 inhibitors (sildenafil, tadalafil) — severe hypotension; at least 6 hours gap recommended
  • Micturition syncope
  • Benign prostatic hyperplasia with upper urinary tract complications (urinary retention risk)

Side effects

  • Postural hypotension (first-dose effect — take at bedtime)
  • Dizziness/syncope
  • Fatigue
  • Peripheral oedema
  • Palpitations
  • Intraoperative floppy iris syndrome (IFIS) — inform ophthalmologist before cataract surgery

Interactions

  • PDE-5 inhibitors (sildenafil, tadalafil, vardenafil) — additive hypotension; 6-hour gap minimum; avoid combination where possible
  • Other antihypertensives — additive BP lowering
  • NSAIDs — blunt antihypertensive effect

Monitoring

  • Blood pressure (lying and standing — postural component)
  • Urinary symptoms (BPH response)
  • Peripheral oedema
  • Syncope/fall history in elderly

Reference: BNFc; BNF 90; PATHWAY-2 Trial (Williams et al. Lancet 2015); NICE NG136 (Hypertension); NICE CG97 (BPH); SPC Cardura. Verify against your local formulary and the latest BNF before prescribing.

Related

Curated clinical cross-links plus same-class fallbacks.

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