What the label lists and what reports show
Tadalafil side effects
Tadalafil's FDA label: “Most common adverse reactions (≥2%) include headache, dyspepsia, back pain, myalgia, nasal congestion, flushing, and pain in limb ( 6.1 ).” FAERS holds 99,551 reports naming it through July 30, 2026; the reaction reported most often, leaving out the conditions it is used for, product-use terms and outcomes, is dyspnoea (11,993 reports).
- Generic listed
Check it at the source: the tadalafil FDA label on DailyMed (effective June 3, 2026, Eli Lilly and Company); the FDA FAERS public dashboard.
What does the label list?
From the label: adverse reactionsMost common adverse reactions (≥2%) include headache, dyspepsia, back pain, myalgia, nasal congestion, flushing, and pain in limb ( 6.1 ).
Table 2: Treatment-Emergent Adverse Reactions Reported by ≥2% of Patients Treated with CIALIS for Once Daily Use (2.5 or 5 mg) and More Frequent on Drug than Placebo in the Three Primary Placebo-Controlled Phase 3…
| Adverse Reaction | Placebo (N=248) | Tadalafil 2.5 mg (N=196) | Tadalafil 5 mg (N=304) |
|---|---|---|---|
| Headache | 5% | 3% | 6% |
| Dyspepsia | 2% | 4% | 5% |
| Nasopharyngitis | 4% | 4% | 3% |
| Back pain | 1% | 3% | 3% |
| Upper respiratory tract infection | 1% | 3% | 3% |
| Flushing | 1% | 1% | 3% |
| Myalgia | 1% | 2% | 2% |
| Cough | 0% | 4% | 2% |
| Diarrhea | 0% | 1% | 2% |
| Nasal congestion | 0% | 2% | 2% |
| Pain in extremity | 0% | 1% | 2% |
| Urinary tract infection | 0% | 2% | 0% |
| Gastroesophageal reflux disease | 0% | 2% | 1% |
| Abdominal pain | 0% | 2% | 1% |
Rows and numbers as the label prints them, under its own column headings (the first rows of a longer table where it runs on). A reaction in a trial table is not necessarily caused by the medicine, and trials differ from everyday use.
From the label: adverse reactions, continuedMost common adverse reactions (≥2%) include headache, dyspepsia, back pain, myalgia, nasal congestion, flushing, and pain in limb ( 6.1 ). To report SUSPECTED ADVERSE REACTIONS, contact Eli Lilly and Company at 1-800-LillyRx (1-800-545-5979) or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Tadalafil was administered to over 9000 men during clinical trials worldwide. In trials of CIALIS for once daily use, a total of 1434, 905, and 115 were treated for at least 6 months, 1 year, and 2 years, respectively. For CIALIS for use as needed, over 1300 and 1000 subjects were treated for at least 6 months and 1 year, respectively. CIALIS for Use as Needed for ED In eight primary placebo-controlled clinical studies of 12 weeks duration, mean age was 59 years (range 22 to 88) and the discontinuation rate due to adverse events in patients treated with tadalafil 10 or 20 mg was 3.1%, compared to 1.4% in placebo treated patients.
Source: FDA drug label, Eli Lilly and Company, effective June 3, 2026 (SPL set bcd8f8ab-81a2-4891-83db-24a0b0e25895), via openFDA; the full label on DailyMed
What do FAERS reports show?
99,551 reports list tadalafil among the medicines taken, each a report of something that happened, not proof the medicine caused it; 11,120 are coded as a death and 37,358 as a hospital stay. Counts follow how widely a medicine is used and watched, and they are not a measure of how risky it is. Of the 21 reactions below, 15 are named by the same term (in US spelling) in the label's adverse reactions, warnings or patient leaflet; a reaction the label does not name may still be there under another word, and a report does not show that the medicine caused it.
Reports received each year
The 25 most reported reactions
Source: FDA Adverse Event Reporting System (FAERS) via openFDA, reports through July 30, 2026; reactions as MedDRA preferred terms
What next?
- Tadalafil: the full record
- label, generics, price, shortages, recalls
- Report a side effect to the FDA
- MedWatch
- Side effects hub
- the most reported medicines and reactions