Tadalafil Side Effects: Common, Rare & Heart Risks
Tadalafil Side Effects: What You Should Know
This guide breaks down what’s common, what’s rare, and what specifically to know about tadalafil and heart health. It doesn’t replace a conversation with your own doctor or pharmacist.
What Is Tadalafil and How Does It Work?
Tadalafil is a phosphodiesterase type 5 (PDE5) inhibitor. It’s FDA-approved under the brand name Cialis for erectile dysfunction (ED) and benign prostatic hyperplasia (BPH), and under the brand name Adcirca for pulmonary arterial hypertension (PAH). It works by relaxing blood vessels, which increases blood flow to specific tissues. Any use outside these approved indications, including use without a prescription or diagnosis, falls outside the safety data described here.
Common Side Effects of Tadalafil
The most frequently reported side effects across clinical trials are headache, indigestion (dyspepsia), back pain, muscle aches (myalgia), flushing, and stuffy or runny nose. Other commonly reported effects include nasal/throat irritation and pain in the extremities.
- Headache: the single most commonly reported adverse reaction
- Indigestion / upset stomach
- Flushing
- Stuffy or runny nose
- Back pain and muscle aches: these can appear 12 to 24 hours after taking tadalafil and typically resolve within about two days. Over-the-counter pain relievers are generally effective, though a small percentage of patients in trials needed further care.
These effects are consistent with tadalafil’s mechanism as a mild vasodilator.
Tadalafil 20 mg Side Effects: Does a Higher Dose Mean More Risk?
Side effect frequency with tadalafil tends to increase somewhat with dose. Headache and upset stomach, for example, are reported more often at 20 mg than at 5 mg. This is why prescribers typically start at a lower dose and adjust based on response and tolerability, and why the “as-needed” 20 mg dose and the lower-dose daily formulation are prescribed differently. Any change in dose should be made with a prescriber, not independently.
Serious (Rare) Side Effects: When to Seek Emergency Care
Most tadalafil side effects are mild and temporary, but a small number of reactions require immediate medical attention.
Priapism (a prolonged erection). An erection lasting longer than four hours is a medical emergency; seeking prompt care helps avoid lasting damage to erectile tissue.
Sudden vision loss. Rare reports describe sudden decreased or lost vision in one or both eyes among men taking PDE5 inhibitors including tadalafil, sometimes associated with a condition called non-arteritic ischemic optic neuropathy (NAION). Anyone experiencing sudden vision changes should stop the medication and seek care immediately.
Sudden hearing loss. Similarly rare reports describe sudden hearing decrease or loss, sometimes with ringing in the ears or dizziness.
Heart attack symptoms. Chest pain or pressure, pain spreading to the jaw or shoulder, nausea, and sweating during or after sexual activity should be treated as a possible emergency.
Allergic reaction. Rash, hives, swelling of the lips/tongue/throat, or difficulty breathing or swallowing warrant immediate medical help.
Tadalafil Side Effects on the Heart
This is one of the most searched, and most misunderstood, parts of tadalafil’s safety profile.
The nitrate interaction is a contraindication, not just a caution. Tadalafil must not be combined with nitrate medications (such as isosorbide dinitrate or isosorbide mononitrate, often prescribed for chest pain), or with recreational nitrite drugs sometimes called “poppers.” The combination can cause a severe, unsafe drop in blood pressure.
What the broader cardiovascular data shows. Clinical evaluations of PDE5 inhibitors, including tadalafil, have not found a clinically significant effect on cardiac electrophysiology (such as QT prolongation) that would suggest increased cardiac risk. A 2024 systematic review and meta-analysis pooling over 1.2 million subjects across 16 cohort studies found that PDE5 inhibitor use, including tadalafil, was associated with a lower rate of major adverse cardiovascular events (MACE) and all-cause mortality compared with non-use.
Important: these are observational, association-based findings, not evidence that tadalafil actively protects the heart or reduces cardiovascular risk for any individual. They should not be read as a treatment benefit. Men with cardiovascular disease, a recent heart attack or stroke, or unstable angina should be evaluated by a physician before using tadalafil.
Who needs extra caution:
- Men taking alpha-blockers for blood pressure or an enlarged prostate (risk of additive blood-pressure-lowering effects)
- Men with a history of heart disease, low or uncontrolled blood pressure, or a recent cardiac event
- Men who drink alcohol heavily while taking tadalafil, which can compound blood-pressure and heart-rate effects
Long-Term Side Effects of Tadalafil (Daily-Use Data)
For men prescribed a lower-dose, once-daily tadalafil (rather than the as-needed 20 mg dose), longer clinical trials have tracked side effects over time. In studies of daily dosing, discontinuation due to adverse events occurred in roughly 3.6% to 4.1% of tadalafil-treated patients compared with about 1.6% to 2.8% of those on placebo. In a one-year open-label extension study, back pain and muscle aches were reported in 5.5% and 1.3% of patients, respectively. Most patients who experienced back pain or myalgia on tadalafil did not need to stop treatment because of it: about 0.5% discontinued for that specific reason.
Who Should NOT Take Tadalafil
Severe liver impairment
Tadalafil/Cialis allergy
Prior NAION
- Anyone currently taking any form of organic nitrate medication
- Anyone with a known serious allergy to tadalafil or Cialis
- Men with severe hepatic (liver) impairment
- Men advised against sexual activity due to underlying heart conditions
- Anyone with a prior episode of NAION (a specific type of vision loss), per prescriber judgment
This list is not exhaustive. A prescriber will review full medical history, current medications, and health conditions before prescribing tadalafil.
Tadalafil Drug Interactions to Know
- Nitrates: contraindicated; risk of severe hypotension
- Alpha-blockers: use with caution due to additive blood-pressure-lowering effects
- Other PDE5 inhibitors (e.g., sildenafil): should not be combined with tadalafil
- Alcohol: heavy consumption alongside tadalafil can increase the risk of headache, dizziness, rapid heart rate, or low blood pressure
A note on unverified, compounded, or counterfeit tadalafil: Tadalafil is widely counterfeited and sold outside legitimate pharmacy channels. Products marketed as “natural tadalafil” supplements, unregulated compounded versions, or medication purchased from unverified online sellers may contain incorrect dosing, contaminants, or no active ingredient verification at all. Only use tadalafil obtained through a licensed prescriber and a legitimate, verified pharmacy.
When to See a Doctor
Contact a healthcare provider promptly if you experience:
- An erection lasting more than 4 hours
- Sudden vision or hearing changes
- Chest pain, pain radiating to the jaw/arm, or shortness of breath
- Signs of a severe allergic reaction
- Any side effect that is severe, persistent, or worsening
Tadalafil Dosage Forms at a Glance
| Form | Typical Use | Approx. Onset | Duration | Notes |
|---|---|---|---|---|
| 5 to 20 mg (as needed) | ED, taken before sexual activity | About 30 to 60 min (varies) | Up to about 36 hours | Per label guidance, dosing frequency is limited at the higher end |
| 2.5 to 5 mg (once daily) | ED and/or BPH, continuous use | Steady-state dosing | Continuous | Lower per-dose side-effect burden reported in some trials |
| Adcirca-labeled use | PAH | N/A | Continuous, per prescriber | Requires regular monitoring |
This table is general educational information, not a dosing instruction. Dose must be individualized by a prescriber.
Frequently Asked Questions
What is the most common side effect of tadalafil?
Headache is the most commonly reported single side effect, along with indigestion, back pain, muscle aches, flushing, and nasal congestion.
Is it bad to take tadalafil every day?
Once-daily, low-dose tadalafil is an FDA-approved regimen for ED and BPH. It carries its own side-effect profile studied in longer trials and should only be used as prescribed and monitored by a doctor.
What should you not take with tadalafil?
Nitrate medications are contraindicated. Alpha-blockers, other PDE5 inhibitors, and heavy alcohol use require caution or avoidance.
Does tadalafil affect your heart long-term?
Available cardiovascular trial and cohort data have not shown an increased risk of major cardiac events from tadalafil in appropriately screened patients, and some large observational studies report a lower rate of cardiovascular events among tadalafil users. However, tadalafil remains contraindicated with nitrates due to a serious blood-pressure interaction, and anyone with existing heart disease should be evaluated before starting treatment.
How long does tadalafil stay in your system?
Tadalafil is known for a long duration of action, remaining effective for up to approximately 36 hours after a single as-needed dose, which is one reason back pain or muscle aches can appear a day after dosing.
The Bottom Line
Tadalafil’s side-effect profile is well studied: most people experience mild, short-lived effects like headache or back pain, while serious reactions are rare but require immediate attention. The clearest safety rule is also the simplest: never combine tadalafil with nitrate medications, and always source it through a licensed prescriber and pharmacy. If you’re considering tadalafil or already taking it and have questions about a symptom, talk to your doctor or pharmacist. They can review your full health history and current medications to confirm it’s right for you.