PDE5 inhibitor Pregnancy: Tadalafil tablets are not indicated for use in females; there are no data with the use of tadalafil in pregnant women. In animal reproduction studies no adverse developmental effects were observed at exposures up to 11 times the maximum recommended human dose of 20 mg/day. (The UK ADCIRCA SPC advises that, as a precautionary measure, use during pregnancy is preferably avoided, and that it should not be used during breast-feeding.)

Tadalafil

Brand names: Cialis, Adcirca

Tadalafil is an oral long-acting phosphodiesterase type-5 inhibitor used for erectile dysfunction and for the symptoms of benign prostatic hyperplasia, and (as a separate product) for pulmonary arterial hypertension.

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: Erectile dysfunction, as-needed use: starting dose 10 mg taken prior to anticipated sexual activity, increased to 20 mg or decreased to 5 mg based on efficacy and tolerability. Erectile dysfunction, once-daily use: starting dose 2.5 mg once daily, may be increased to 5 mg. Benign prostatic hyperplasia (and combined ED/BPH): 5 mg once daily, taken at approximately the same time every day

Route: Oral — may be taken without regard to food; do not split tablets, the entire dose should be taken

Frequency: As-needed use: maximum once per day. Once-daily use: once daily at approximately the same time every day

Max: 20 mg as needed, not more than once per day. With potent CYP3A4 inhibitors (e.g. ketoconazole, ritonavir): as-needed maximum 10 mg not more than once every 72 hours; once-daily maximum 2.5 mg

SOURCE / INDICATION CAVEAT — READ FIRST: the UK SPC fetched in this bundle is ADCIRCA 20 mg film-coated tablets (eMC product 5745), which is tadalafil for PULMONARY ARTERIAL HYPERTENSION, a different indication from this urology PDE5-inhibitor page. Its adult dose is 40 mg (two × 20 mg tablets) once daily, initiated and monitored by a physician experienced in the treatment of PAH — that figure must NOT be applied to erectile dysfunction or BPH. Because no UK SPC for the ED/BPH tadalafil product was retrieved, the regimen above is taken from the US FDA prescribing information (tadalafil tablets, A-S Medication Solutions, label date 2024-10-16, DailyMed setid e7caaf8f-10ff-4637-82e0-d152f4029bce), which does cover ED and BPH; a clinician must verify it against the UK ED/BPH SPC before publication. Additional points from the US label: as-needed tadalafil improved erectile function compared with placebo up to 36 hours after dosing; when BPH therapy is initiated with tadalafil and finasteride, the dose is 5 mg once daily for up to 26 weeks; tadalafil is not recommended in combination with alpha-blockers for the treatment of BPH, and when used for ED in men taking an alpha-blocker the patient should be stable on alpha-blocker therapy first and tadalafil started at the lowest recommended dose. Hepatic impairment (as-needed): mild or moderate (Child-Pugh A or B) — dose should not exceed 10 mg once per day; severe (Child-Pugh C) — not recommended. Paediatric: the US label states tadalafil tablets are not indicated for use in paediatric patients and that safety and efficacy below 18 years have not been established (the age/weight-banded paediatric dosing in the ADCIRCA SPC belongs to the PAH indication only and is not reproduced here).

Dose adjustments

Renal

As-needed use: creatinine clearance 30 to 50 mL/min — starting dose 5 mg not more than once per day, maximum 10 mg not more than once every 48 hours; creatinine clearance <30 mL/min or on haemodialysis — maximum 5 mg not more than once every 72 hours. Once-daily use for ED: not recommended if creatinine clearance <30 mL/min or on haemodialysis. Once-daily use for BPH or ED/BPH: creatinine clearance 30 to 50 mL/min — starting dose 2.5 mg, may be increased to 5 mg based on individual response; creatinine clearance <30 mL/min or on haemodialysis — not recommended.

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.

Contraindications

Use of any form of organic nitrate, regularly and/or intermittently — tadalafil potentiates the hypotensive effect of nitrates
Concomitant guanylate cyclase stimulators such as riociguat
Known serious hypersensitivity to tadalafil (hypersensitivity reactions have included Stevens-Johnson syndrome and exfoliative dermatitis)
From the UK ADCIRCA SPC (PAH product): acute myocardial infarction within the last 90 days; severe hypotension (<90/50 mmHg); loss of vision in one eye because of non-arteritic anterior ischaemic optic neuropathy (NAION)

Side effects

Headache
Dyspepsia (including abdominal pain/discomfort) and nausea
Back pain and myalgia
Nasal congestion / nasopharyngitis and flushing
Pain in limb; less commonly hypotension, palpitations, blurred vision, and rarely NAION or sudden hearing loss

Interactions

Nitrates — contraindicated; if nitrate administration is deemed medically necessary in a life-threatening situation, at least 48 hours should elapse after the last tadalafil dose, and then only under close medical supervision with haemodynamic monitoring
Guanylate cyclase stimulators (e.g. riociguat) — contraindicated; PDE5 inhibitors may potentiate their hypotensive effects
Alpha-blockers, antihypertensives or substantial amounts of alcohol (≥5 units) — may lead to hypotension; caution advised
Potent CYP3A4 inhibitors (e.g. ketoconazole, ritonavir) — increase tadalafil exposure; as-needed dose limited to 10 mg not more than once every 72 hours, once-daily dose limited to 2.5 mg
CYP3A4 inducers (e.g. rifampin) — decrease tadalafil exposure

Clinical monograph

How it works

It selectively inhibits phosphodiesterase type-5, increasing cyclic GMP and enhancing nitric-oxide-mediated smooth muscle relaxation in the corpus cavernosum and lower urinary tract.

Prescribing in practice

Co-administration with any nitrate or nicorandil is contraindicated because of the risk of profound, potentially fatal hypotension.
Caution with alpha-blockers and other antihypertensives owing to additive blood-pressure lowering, and avoid in recent cardiovascular events or unstable angina.
Dose adjustment or avoidance applies in severe renal or hepatic impairment and with potent CYP3A4 inhibitors.

Monitoring

Assess cardiovascular fitness for sexual activity before starting and review efficacy and tolerability, including any postural symptoms.

Counselling the patient

Do not use with nitrate medicines or recreational nitrates ('poppers').
Seek urgent care for a painful erection lasting several hours or for sudden visual or hearing loss.

Evidence & guidelines

Randomised trials support PDE5 inhibitors as first-line oral therapy for erectile dysfunction and demonstrate symptomatic benefit in benign prostatic hyperplasia.

Reference: NICE CG97; ESC; 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

Tadalafil (BPH) · PDE5 Inhibitor

Pathways