What Is Tadalafil? Uses, Dosage, and What You Need to Know in 2026

Tadalafil Is a Prescription Medication Used to Treat Erectile Dysfunction, Enlarged Prostate, and Pulmonary Arterial Hypertension

Tadalafil is a phosphodiesterase-5 (PDE5) inhibitor — a class of medication that relaxes blood vessels and increases blood flow to specific areas of the body. It's one of the most commonly prescribed medications in the United States and is best known as the active ingredient in Cialis.

Whether you've just been prescribed Tadalafil or you're researching it for the first time, this guide covers everything you need to know: what it's used for, how to take it, who should avoid it, and what it costs in 2026.

What Is Tadalafil?

Brand and Generic Names

Tadalafil is the generic name. It's sold under several brand names:

• Cialis — for erectile dysfunction (ED) and benign prostatic hyperplasia (BPH)
• Adcirca — for pulmonary arterial hypertension (PAH)
• Alyq — a generic alternative to Adcirca for PAH

Drug Class

Tadalafil belongs to the PDE5 inhibitor class, which also includes Sildenafil (Viagra), Vardenafil (Levitra), and Avanafil (Stendra). To understand how this class of drugs works, see our guide to Tadalafil's mechanism of action.

Manufacturer

Brand Cialis and Adcirca are manufactured by Eli Lilly and Company. Generic Tadalafil is produced by multiple manufacturers, which keeps prices competitive.

FDA Approval

Tadalafil was first approved by the FDA in 2003 for ED, with additional approvals for PAH (2009) and BPH (2011). Generic versions became available in 2018.

Controlled Substance Status

Tadalafil is not a controlled substance. It does not have a DEA schedule designation.

What Is Tadalafil Used For?

Erectile Dysfunction (ED)

Tadalafil helps men achieve and maintain an erection during sexual stimulation. It doesn't cause spontaneous erections — sexual arousal is still required. Tadalafil is unique among PDE5 inhibitors because it can be taken daily at a low dose, providing readiness around the clock rather than requiring planning before sexual activity.

Benign Prostatic Hyperplasia (BPH)

Tadalafil 5 mg daily is FDA-approved to treat the symptoms of enlarged prostate, including difficulty urinating, weak stream, and frequent or urgent urination. It can treat BPH alone or in combination with ED.

Pulmonary Arterial Hypertension (PAH)

Under the brand names Adcirca and Alyq, Tadalafil 40 mg daily is used to treat high blood pressure in the lungs, improving exercise capacity and slowing disease progression.

Off-Label Uses

Some doctors prescribe Tadalafil off-label for Raynaud's phenomenon, lower urinary tract symptoms, and altitude sickness prevention, though these uses are less well-studied.

How Is Tadalafil Taken?

Tadalafil comes in oral tablet form in four strengths: 2.5 mg, 5 mg, 10 mg, and 20 mg.

As-Needed for ED

• Starting dose: 10 mg taken at least 30 minutes before sexual activity
• May be adjusted to 5 mg or 20 mg based on effectiveness and side effects
• Maximum: one dose per day
• Can be taken with or without food

Daily Use for ED or BPH

• Dose: 2.5 mg or 5 mg once daily at the same time each day
• Works continuously — no need to plan around sexual activity
• Can be taken with or without food

For PAH

• Dose: 40 mg (two 20 mg tablets) once daily
• Prescribed and monitored by a specialist

Important: Do not take Tadalafil with grapefruit juice, which can increase drug levels in your blood and raise the risk of side effects.

Who Should Not Take Tadalafil?

Tadalafil is not safe for everyone. You should not take it if you:

• Take nitrates in any form — including Nitroglycerin, Isosorbide Mononitrate, Isosorbide Dinitrate, or amyl nitrite ("poppers"). Combining these with Tadalafil can cause a dangerous drop in blood pressure.
• Take Riociguat (Adempas) — another pulmonary hypertension drug that interacts dangerously with Tadalafil.
• Have a known allergy to Tadalafil or any of its ingredients.
• Have been advised against sexual activity by your doctor due to cardiovascular risk.

Use caution if you have liver or kidney disease, a history of stroke or heart attack, low blood pressure, or if you take alpha-blockers. For a full list of interactions, see our Tadalafil drug interactions guide.

For information on side effects, including common and serious ones, see our Tadalafil side effects guide.

How Much Does Tadalafil Cost?

Cost varies significantly between brand and generic:

• Brand Cialis: $350–$450 for 30 tablets without insurance
• Generic Tadalafil: $9–$45 for 30 tablets with a discount coupon
• Lowest price: As low as $0.31 per tablet (5 mg) with a GoodRx coupon

Insurance Coverage

Generic Tadalafil for BPH is often covered by insurance and Medicare Part D. However, ED prescriptions are frequently excluded or require prior authorization. Brand Cialis is generally not covered by Medicare for ED.

Saving Money

Discount programs like GoodRx, SingleCare, and RxSaver offer significant savings on generic Tadalafil. The Lilly Cares Foundation Patient Assistance Program may help uninsured patients get brand Cialis at no cost based on income. For a complete breakdown, see our guide to saving money on Tadalafil.

How Does Tadalafil Compare to Other ED Medications?

Tadalafil's biggest advantage is its long duration of action — up to 36 hours, compared to 4–6 hours for Sildenafil (Viagra) and Vardenafil (Levitra). This is why Tadalafil is sometimes called the "weekend pill." It's also the only PDE5 inhibitor approved for daily use and for BPH.

For alternatives, see our guide on alternatives to Tadalafil.

Final Thoughts

Tadalafil is a well-established, versatile medication that treats ED, BPH, and PAH. Generic versions have made it significantly more affordable, and it can be prescribed by primary care doctors, urologists, or through telehealth. If you've been prescribed Tadalafil and need to fill it, Medfinder can help you find a pharmacy with it in stock near you.