Tadalafil

One ingredient across products and indications

Tadalafil inhibits PDE5, an enzyme involved in blood-vessel relaxation. Cialis and many generics are tablets used for erectile dysfunction and symptoms of an enlarged prostate. Adcirca and the oral suspension Tadliq treat group 1 pulmonary arterial hypertension. The strength, formulation and indication belong to the particular product.^619,620,621

Food by formulation

Cialis and Adcirca tablets can be taken with or without food. US Tadliq suspension also permits food. EU Adcirca suspension carries a fasting instruction because its food effect has not been studied.^619,621,622

Where it has evidence

Erectile dysfunction

A pooled analysis of five randomized trials included 1,112 men treated for 12 weeks. In the 20 mg group, the erectile-function score improved by 7.9 points and 81% reported improved erections, compared with 35% on placebo. These trials used treatment as needed. A separate 268-man trial studied daily treatment.^623,624

Urinary symptoms from an enlarged prostate

In a 325-man trial, symptom scores improved by 5.6 points with tadalafil and 3.6 with placebo after 12 weeks. Peak urinary flow and residual urine did not differ significantly. The evidence is strongest for symptom relief.⁶²⁵

Pulmonary arterial hypertension

PHIRST enrolled 405 people with PAH. The 40 mg group met the primary endpoint after 16 weeks, with a 33 m mean placebo-adjusted improvement in six-minute walking distance. EMA also reports a 26 m median estimate from the same trial. Those figures use different statistical summaries.^626,622

Combination treatment

Trials also support tadalafil combined with ambrisentan or macitentan in selected PAH populations. Opsynvi contains macitentan and tadalafil in one tablet. Its embryo-fetal boxed warning applies to that combination.^627,628,629

Heart, brain and exercise claims

Dementia and cognition

The favorable dementia headlines come largely from observational studies of PDE5 inhibitors. In one large study, the tadalafil-specific result with a three-year lag was not statistically significant. The newer ETLAS-2 trial studied people with cerebral small-vessel disease: adherence was worse and adverse events were more frequent with tadalafil. Its 60-person cognitive analysis found no overall benefit.^630,631,632

Heart and lung disease need precise names

PASSION studied a different condition from group 1 PAH: heart failure with preserved ejection fraction and combined post- and precapillary pulmonary hypertension. It stopped early after 125 of a planned 372 participants because of drug supply. The primary outcome did not improve, and the mortality estimate raised concern but was imprecise.⁶³³

Workout claims

A crossover trial in 14 healthy male athletes found no improvement in maximal oxygen uptake or ventilatory thresholds after a single oral 20 mg dose under normal oxygen conditions. The 331-boy Duchenne muscular dystrophy trial also failed its main walking outcome.^634,635

Fertility, side effects and interactions

The fertility answer needs both studies

Two six-month studies found no adverse group effect on semen measures. A separate nine-month study found sperm-concentration drops of at least 50% in 12 of 95 tadalafil participants and 2 of 96 placebo participants. It still passed its prespecified noninferiority test, which allowed a 20-percentage-point margin. Neither program measured pregnancy or live birth.^636,637

Common side effects

Headache, indigestion, back pain and muscle aches are common. In the as-needed ED trials, headache occurred in 15% of participants taking 20 mg and 5% taking placebo. In daily 5 mg ED trials, the figures were 6% and 5%.^619,620

When to get urgent help

Get urgent care for an erection lasting more than four hours, sudden loss or decrease of vision, or sudden hearing loss. Tell the treating clinician when tadalafil was last taken, particularly during care for chest pain.⁶¹⁹

Regional research

China and Russia

Chinese studies in 2021 and 2026 compared the blood concentrations produced by test and reference tadalafil tablets in healthy men. Russian evidence includes a 60-person study of endothelial measures over four weeks and a separate uncontrolled diabetes and prediabetes study.^{638,639,640,641}

Older patients in Japan

A Japanese study reviewed 84 patients aged 75 or older with urinary symptoms. Its analysis followed the 71 who continued treatment through 24 weeks. Symptoms improved, nine patients reported adverse events and five stopped treatment. The lack of a comparator and exclusion of early discontinuers limit the result.⁶⁴²

Product quality

Swissmedic found quality defects in 67 of 140 seized products represented as tadalafil. FDA and Health Canada also publish specific contamination and counterfeit notices, including a Canadian counterfeit Cialis alert in January 2026.^643,644,645

Common questions

The questions readers ask, answered from the studies.

01 Are generic tadalafil, Cialis, Adcirca, and Tadliq the same drug?

Generic tadalafil, Cialis, Adcirca, Tadliq, and Chewtadzy share tadalafil as the active ingredient, but their formulation, indication, and market status differ. Cialis tablets cover erectile dysfunction and BPH symptoms, while Adcirca tablets and Tadliq oral suspension are PAH products. FDA approved Chewtadzy chewables in 2024, but the agency says they were never marketed.^{619,620,621,646}

02 What side effects should I watch for?

Common Cialis effects include headache, indigestion, back pain, muscle aches, nasal congestion, flushing, and limb pain. Rates change with the product, population, and regimen: in the Adcirca PAH trial, headache occurred in 42% with tadalafil 40 mg and 15% with placebo.^619,620

03 How long does tadalafil take to work, and how long can it last?

The Cialis patient leaflet says an erectile response may be possible from 30 minutes after an as-needed dose and up to 36 hours afterward. Sexual stimulation is still needed. Timing varies between people; the label gives a 17.5-hour mean terminal half-life in healthy adults.⁶¹⁹

04 Why are the doses different for ED, BPH, and PAH?

The dose differs because the products and clinical uses were studied separately. Cialis has as-needed and once-daily erectile-dysfunction regimens and a once-daily BPH regimen; Adcirca is a once-daily PAH product. Kidney function, liver function, interacting medicines, and formulation also affect the label instructions.^619,620,622

05 How well does tadalafil work for erectile dysfunction?

Five 12-week randomized trials included 1,112 men with erectile dysfunction. In the 20 mg as-needed arm, the erectile-function score improved by 7.9 points from baseline, 75% of intercourse attempts were successful, and 81% reported improved erections versus 35% with placebo.⁶²³

06 Which tadalafil interactions can be dangerous?

Organic nitrates and guanylate-cyclase stimulators such as riociguat are contraindicated because blood pressure can fall dangerously. Alpha blockers, other blood-pressure medicines, substantial alcohol intake, and strong CYP3A4 inhibitors or inducers can also change risk or exposure. The label's 48-hour nitrate passage is for a life-threatening emergency under medical supervision.^619,620

07 Does tadalafil protect the heart or improve workouts?

A crossover study in 14 healthy male athletes found that one 20 mg dose did not improve VO2max or ventilatory thresholds during exercise in normal oxygen conditions. A claims-database study found fewer cardiovascular events among men with tadalafil claims, but it cannot show that tadalafil caused the difference. Short vessel-ultrasound trials had conflicting results.^{634,647,648,649}

08 What is the difference between daily and as-needed tadalafil?

As-needed Cialis is taken in relation to anticipated sexual activity and is labeled for no more than one dose per day. Once-daily Cialis is taken without regard to the timing of sexual activity and is also the labeled pattern for BPH symptoms. Daily tadalafil reaches steady-state blood levels in about five days.⁶¹⁹

09 Does tadalafil help urinary symptoms or shrink the prostate?

In a 12-week trial of 325 men, the urinary symptom score changed by -5.6 with tadalafil and -3.6 with placebo. Maximum urinary flow and residual urine did not improve significantly. The trial measured symptom relief; prostate shrinkage was not an outcome.⁶²⁵

10 How does tadalafil compare with sildenafil or Viagra?

A review of 16 randomized and nonrandomized controlled trials found similar erectile-function efficacy and overall adverse-event rates for tadalafil and sildenafil. Preference and some psychological outcomes favored tadalafil; back pain and muscle aches were more common with tadalafil, while flushing was less common.⁶⁵⁰

11 When do vision, hearing, or erection problems need urgent help?

An erection lasting more than four hours needs emergency care. The Cialis label also says to stop the medicine and seek care for sudden vision loss, and to seek prompt care for sudden hearing decrease or loss. These warnings apply even when the symptom is painless.^619,620

12 What does tadalafil do for pulmonary arterial hypertension?

PHIRST randomized 405 people with pulmonary arterial hypertension for 16 weeks. In the 40 mg group, the placebo-adjusted change in six-minute walk distance was a median 26 meters and a mean 33 meters. Only that arm met the trial's prespecified threshold.^626,622

13 How much does tadalafil cost?

FDA records include approved generic tadalafil products. FDA says an approved generic must match the brand product in active ingredient, strength, dosage form, route, and bioequivalence, and competition generally lowers cost. A person's price still varies by product, pharmacy, insurance, and location.^651,652

14 Can tadalafil stop working or cause tolerance?

A post hoc analysis followed 93 tadalafil-treated and 47 placebo-treated men for six months. Successful-intercourse responses were 74% after one month and 78% after six months, while the erectile-function score was unchanged between months three and six. This supports maintained response over six months in that study.⁶⁵³

15 Does tadalafil affect sperm or fertility?

Two six-month trials in 421 men age 45 or older found no adverse group effect on sperm measures or reproductive hormones. In a separate nine-month trial, a 50% or greater sperm-concentration reduction occurred in 12 of 95 tadalafil participants and 2 of 96 placebo participants; the trial still declared noninferiority under its prespecified 20 percentage-point margin. Those trials did not measure pregnancy or live-birth outcomes.^{636,637,619,620}