What Is Tadalafil Used For? The Three Approved Uses

One drug, three labeled uses, and two different prescriptions. What each label and trial says, and what is not a labeled use.

Tadalafil is a phosphodiesterase 5 (PDE5) inhibitor approved in the United States for three conditions: erectile dysfunction (ED), the signs and symptoms of benign prostatic hyperplasia (BPH, an enlarged prostate), and pulmonary arterial hypertension (PAH).¹² The first two are covered by the Cialis label and share a tablet; PAH is covered by separate labels for Adcirca, its generic Alyq and an oral suspension, Tadliq, which use a different dose.²⁴⁵ This guide sets out what each label says tadalafil is used for, what the trials behind each use measured, and what is not a labeled use.

What is tadalafil used for?

The PAH products are a separate prescription from the one used for ED, so a man taking one should not add the other without his prescriber's direction: the Adcirca label says the safety and efficacy of taking it together with another PDE5 inhibitor has not been studied and tells patients not to take other PDE5 inhibitors.²

How is tadalafil used for erectile dysfunction?

Tadalafil was studied for ED in 22 clinical trials of up to 24 weeks involving more than 4,000 patients, including seven placebo-controlled 12-week trials in the general ED population and further studies in men with diabetes and men who developed ED after nerve-sparing radical prostatectomy.¹ The label's three primary measures were the erectile function domain of the International Index of Erectile Function and two questions from the Sexual Encounter Profile diary.¹

Cialis has two dosing schedules. As needed, most men start at 10 mg before anticipated sexual activity, with the dose raised to 20 mg or lowered to 5 mg based on response and tolerability, and the maximum frequency is once a day in most patients.¹ For once-daily use the ED dose is 2.5 mg, which may be raised to 5 mg, taken without regard to the timing of sexual activity.¹ The label also says tablets should not be split and that tadalafil may be taken without regard to food.¹ Our guide to tadalafil doses goes through both schedules, and tadalafil 5 mg and tadalafil 20 mg cover those strengths.

How is tadalafil used for an enlarged prostate?

The label dose for BPH is 5 mg once daily at about the same time each day, whether or not ED is also present.¹ In the two placebo-controlled studies the label reports (748 men with moderate to severe symptoms, mean age 63.2 years), the total International Prostate Symptom Score fell from a baseline of 17.3 by 4.8 points on tadalafil 5 mg against 2.2 points on placebo in Study J, and from 17.1 by 5.6 points against 3.6 points in Study K, both statistically significant at 12 weeks.¹ Peak urine flow rose in both the tadalafil and placebo groups, and the difference between them was not significant.¹

Tadalafil is not the only drug class for BPH. A meta-analysis of seven randomized trials with 1,601 patients found no statistically significant difference between tadalafil and tamsulosin, an alpha-blocker, on total symptom score, quality of life, peak flow or residual urine, with a difference only in erectile function scores favoring tadalafil.³ Two label points matter for anyone on both drug types. The Cialis label does not recommend tadalafil together with alpha-blockers for BPH, and for ED a man should be stable on an alpha-blocker before tadalafil is started at the lowest dose.¹

The prostate use also has a fixed-dose form. Entadfi combines finasteride and tadalafil in one capsule to initiate BPH treatment for up to 26 weeks, because the incremental benefit of tadalafil decreases from 4 weeks until 26 weeks and its benefit beyond 26 weeks is unknown.⁶ The Cialis label carries the same 26 week limit when tadalafil is started together with finasteride.¹

What is tadalafil used for in pulmonary arterial hypertension?

The labels describe the PAH use as improving exercise ability in WHO Group 1 PAH.² The studies establishing effectiveness included mostly patients with NYHA functional class II to III symptoms, with idiopathic or heritable PAH in 61% and PAH associated with connective tissue disease in 23%.² The dose is 40 mg once daily, taken as two 20 mg tablets with or without food, and the label says not to divide the 40 mg over the day.² Alyq is a tablet with the same indication and dose, and Tadliq is an oral suspension given as 40 mg (10 mL) once daily.⁴⁵

Because the PAH dose is made of 20 mg tablets, it is sometimes confused with the ED dose. They are different prescriptions for different conditions, and the products are not interchangeable in purpose.²¹

What is tadalafil not approved for?

The labels list ED, BPH and PAH and nothing else. The Cialis label states that it is not indicated for use in pediatric patients, and reports a 48 week placebo-controlled trial in boys aged 7 to 14 with Duchenne muscular dystrophy that failed to show any benefit on muscle strength or performance.¹ Other uses described online, such as for athletic performance, are not labeled uses, and we found no label support for them. A prescriber may sometimes use a drug for a purpose outside its label, but that is a decision made with a patient's history in hand, not something the product label establishes.

What are the common side effects and warnings?

The Cialis label lists headache, dyspepsia, back pain, myalgia, nasal congestion, flushing and pain in a limb as the most common adverse reactions, each at 2% or more.¹ The label contraindicates tadalafil in anyone using nitrates in any form, and in anyone using a guanylate cyclase stimulator such as riociguat.¹ It tells patients to seek care for an erection lasting more than four hours, for sudden loss of vision in one or both eyes (a possible sign of NAION), and for sudden decrease or loss of hearing.¹ Strong CYP3A4 inhibitors such as ritonavir or ketoconazole cap the as-needed dose at 10 mg no more than once every 72 hours.¹ Our pages on tadalafil side effects, tadalafil and blood pressure and ED medication interactions go deeper on each.

Our pick: Quattro from Vea Health Sponsored

For readers whose reason for asking is ED, Quattro is our pick in this guide because we have a financial relationship with Vea Health. That is the basis for the placement, not a trial result, and we make no claim that it is faster, stronger or safer than tadalafil or any other option.

Vea Health describes Quattro as a compounded sublingual dose combining sildenafil, tadalafil, vardenafil and apomorphine, prescribed only after a licensed clinician reviews a health history.⁷ It is not a Cialis, Adcirca or Alyq tablet, it is used only for ED in the way Vea describes it, and the page we loaded does not list strengths. It is not FDA-approved: the FDA states it does not verify the safety, effectiveness or quality of compounded drugs before they reach patients.⁸ The labels above describe tadalafil alone, and the Adcirca label says taking tadalafil with another PDE5 inhibitor has not been studied, so the label doses and trial results above do not carry over to a multi-drug dose.² It suits a man whose question is ED, who has discussed a multi-drug dissolving format with a clinician and who accepts that it is compounded.

Questions to ask a prescriber

• Is my reason for tadalafil ED, urinary symptoms from an enlarged prostate, or both, and does one daily 5 mg dose cover both?
• Do I take an alpha-blocker for my prostate, a nitrate, or any medicine that affects CYP3A4?
• If I have a lung or heart condition, is the product I am being given the one meant for that condition?
• Should I be checked for another cause of my symptoms first, such as another urological condition?

Safety information

Tadalafil must never be taken with nitrates in any form or with riociguat. An erection lasting more than four hours needs emergency care, as does sudden vision or hearing loss.¹ Only a licensed clinician who knows your history and medicines can say whether tadalafil is appropriate and which product and dose. For how tadalafil compares with the other ED tablets, see sildenafil or tadalafil.

Questions readers ask

What is tadalafil mainly used for?

Erectile dysfunction is the most common use. The Cialis label also lists the signs and symptoms of an enlarged prostate, alone or together with ED, and separate Adcirca, Alyq and Tadliq labels list pulmonary arterial hypertension.

Is tadalafil for the prostate or for ED?

Both, on the Cialis label. The BPH dose is 5 mg once daily, and the same 5 mg daily dose is labeled for men with both conditions.

Is the tadalafil for lung disease the same as for ED?

It is the same drug but a different prescription. The PAH products are dosed at 40 mg once daily, and the Adcirca label says taking it with another PDE5 inhibitor has not been studied.

Is tadalafil used for anything in women?

The labels we read list ED, BPH and PAH and no other use.

Can tadalafil be taken with nitrates?

No. The Cialis label contraindicates tadalafil with any form of organic nitrate and with guanylate cyclase stimulators such as riociguat.

Further reading

Part of our guide: How ED Medications Work: Timing, Food, Interactions and Combinations

• Sildenafil Headache: How Common Is It?
• Tadalafil With Alcohol: How Much Is Too Much?
• Tadalafil Brand Names: Which Brand Is Used for What
• Sildenafil or Tadalafil: How the Two Drugs Differ