Tadalafil in the UK: Complete Guide
How tadalafil works, dosage, NHS vs private prescribing, side effects and drug interactions.
Part of the Access Doctor Erectile Dysfunction guide.
Key fact: Tadalafil (Cialis) lasts up to 36 hours per dose and is unaffected by food — making it uniquely well-suited to men who want spontaneous sex without planning around medication. It is also the only ED medication with a dual licence for ED and benign prostatic hyperplasia (BPH).
Get Tadalafil Online
Access Doctor provides tadalafil via a GPhC-regulated online consultation. No GP appointment required. Discreet next-day delivery.
Start Consultation →What Is Tadalafil?
Tadalafil is an MHRA-approved phosphodiesterase type 5 (PDE5) inhibitor, the same drug class as sildenafil (Viagra), vardenafil (Levitra) and avanafil (Spedra). It was originally licensed under the brand name Cialis (manufactured by Lilly); since the patent expired, generic tadalafil has been widely available in the UK at significantly lower cost.
Unlike sildenafil, tadalafil lasts up to 36 hours and is not affected by food. It is also available as a once-daily low dose (5mg) that provides continuous background coverage without on-demand timing. Tadalafil holds a dual MHRA licence: it is approved for both erectile dysfunction and lower urinary tract symptoms associated with benign prostatic hyperplasia (BPH) — making it the only ED medication licensed for both conditions.
For a head-to-head comparison with sildenafil, see tadalafil vs sildenafil. For a comparison of all four MHRA-approved ED medications, see Viagra vs Cialis vs Levitra vs Spedra.
36 hrs
maximum duration — longest of all four PDE5 inhibitors
~81%
success rate in clinical trials (Goldstein et al.)
2
licensed indications — erectile dysfunction and BPH
Tadalafil Dosage in the UK
| Formulation | Dose | Timing | Duration | Notes |
|---|---|---|---|---|
| On-demand (standard) | 10mg | ~30 min before sex | Up to 36 hours | Recommended starting dose for most men |
| On-demand (increased) | 20mg | ~30 min before sex | Up to 36 hours | If 10mg insufficient; maximum on-demand dose |
| Daily | 5mg | Same time each day | Continuous | For men wanting complete spontaneity or ≥2x/week. Also licensed for BPH. |
| Daily (reduced) | 2.5mg | Same time each day | Continuous | For men over 75 or with significant kidney impairment; BPH starting dose |
Never take more than one on-demand dose in a 24-hour period. Tadalafil can be taken with or without food at any time. For the complete daily tadalafil guide, see daily tadalafil.
How to Get Tadalafil in the UK
Tadalafil is a prescription-only medicine (POM) in all doses in the UK. Unlike sildenafil 50mg (Viagra Connect), there is no over-the-counter tadalafil — a prescriber consultation is required.
| Route | Product | Doses available |
|---|---|---|
| NHS prescription | Generic tadalafil | 5mg, 10mg, 20mg — subject to NHS prescribing criteria |
| Private prescription (online) | Generic tadalafil | 5mg, 10mg, 20mg — via GPhC-registered pharmacy such as Access Doctor |
| Branded private prescription | Cialis (Lilly) | 5mg, 10mg, 20mg — clinically equivalent to generic; significantly more expensive |
Access Doctor’s GPhC-registered pharmacist independent prescribers can assess your suitability for tadalafil via a confidential online consultation in approximately 5 minutes. If appropriate, a prescription is issued and your medication dispatched in plain, unmarked packaging — typically arriving next working day.
Side Effects of Tadalafil
Common (may affect up to 1 in 10)
- Headache — caused by cerebral vasodilation; most common initial side effect
- Facial flushing — usually mild and transient
- Back pain and muscle aches (myalgia) — more common with tadalafil than other PDE5 inhibitors due to its longer systemic presence; typically resolves within 48 hours
- Nasal congestion — less frequent than with sildenafil
- Indigestion — particularly if taken close to a meal
- Dizziness — blood-pressure-lowering effect; avoid standing quickly
Seek immediate emergency care if you experience: priapism (erection lasting more than 4 hours — attend A&E immediately), sudden vision loss, sudden hearing loss, or chest pain. Call 999.
Who Should Not Take Tadalafil
- Men taking nitrate medicines in any form — GTN spray or patches, isosorbide mononitrate or dinitrate, or recreational “poppers” (amyl/butyl nitrite). Absolute contraindication. No exceptions.
- Men taking riociguat (for pulmonary hypertension)
- Men with severe hepatic impairment
- Men with severe hypotension (below 90/50 mmHg) or uncontrolled hypertension (above 170/110 mmHg)
- Men who have had a stroke or myocardial infarction within the past 6 months
- Men advised to avoid sexual activity for cardiovascular reasons
- Men with hereditary degenerative retinal disorders (e.g., retinitis pigmentosa)
Key Drug Interactions
| Drug / class | Interaction | Management |
|---|---|---|
| Nitrates (all forms) | Severe hypotension — potentially fatal | Absolute contraindication |
| Alpha-blockers (tamsulosin, doxazosin) | Additive blood-pressure-lowering | Start at 5mg on-demand; allow 4+ hours between doses |
| CYP3A4 inhibitors (clarithromycin, ketoconazole) | Increased tadalafil plasma levels | Do not exceed 10mg; monitor for adverse effects |
| Ritonavir / HIV protease inhibitors | Markedly increased tadalafil levels | Maximum 10mg every 72 hours |
| Antihypertensives | Additive blood-pressure-lowering | Generally manageable; inform prescriber of all medications |
Frequently Asked Questions
What is tadalafil and how does it work?
Tadalafil is an MHRA-approved PDE5 inhibitor that works by blocking the PDE5 enzyme in penile blood vessels, allowing smooth muscle to relax and blood flow to increase when sexually stimulated. Sexual stimulation is always required.
How long does tadalafil last compared to Viagra?
Tadalafil lasts up to 36 hours per dose — significantly longer than sildenafil (Viagra) which lasts 4–6 hours. This is why tadalafil is called the ‘weekend pill’.
Can I get tadalafil on the NHS?
Yes, under specific criteria. NHS tadalafil is available for men with ED associated with diabetes, multiple sclerosis, Parkinson’s disease, prostate cancer and certain other conditions. Access Doctor provides private prescriptions for men who want faster access.
What is the starting dose of tadalafil?
10mg on-demand is the recommended starting dose for most men. If insufficient, this can be increased to 20mg under prescriber guidance. Daily tadalafil starts at 5mg (or 2.5mg in older men or those with kidney impairment).
Does food affect tadalafil?
No. Tadalafil can be taken with or without food — its absorption is not meaningfully affected by meals. This is a key practical advantage over sildenafil.
What are the main side effects of tadalafil?
Headache, facial flushing, nasal congestion, indigestion, dizziness, and back pain or muscle aches. Visual disturbances are less common with tadalafil than sildenafil.
References
- National Institute for Health and Care Excellence (NICE). Erectile dysfunction: Clinical Knowledge Summary. Updated 2023. cks.nice.org.uk/topics/erectile-dysfunction
- NHS. Erectile dysfunction (impotence). nhs.uk/conditions/erection-problems-erectile-dysfunction
- Carson CC et al. Tadalafil, an oral phosphodiesterase type 5 inhibitor, for the treatment of erectile dysfunction. BJU Int. 2004. PubMed: 15142153
Medical disclaimer: This article is for informational purposes only and does not constitute medical advice. ED treatments are prescription-only medicines requiring clinical assessment. In a medical emergency, call 999.