How does this medication work? What will it do for me?

Tadalafil belongs to a group of medications called phosphodiesterase type 5 inhibitors. It is used to treat erectile dysfunction (male impotence). It helps to achieve and maintain an erection sufficient for sexual activity to occur. It does this by allowing a greater flow of blood into the penis when a man taking the medication is sexually aroused. It works only with sexual stimulation and does not increase sexual desire.

Tadalafil is also used to treat symptoms of benign prostatic hyperplasia (BPH) in men with enlarged prostates. It helps to relieve symptoms such as the frequent need to urinate, painful urination, or the sensation of not completely emptying the bladder. It does this by relaxing muscles in the prostate and bladder. Tadalafil may be used to treat men who experience both erectile dysfunction and BPH.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

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What form(s) does this medication come in?

2.5 mg (for once-a-day use)
Each yellow-orange, almond-shaped, film-coated tablet, marked on one side with "C2½", contains tadalafil 2.5 mg. Nonmedicinal ingredients: croscarmellose sodium, hydroxypropyl cellulose, hydroxypropyl methylcellulose, iron oxide, lactose monohydrate, magnesium stearate, microcrystalline cellulose, sodium lauryl sulfate, talc, titanium dioxide, and triacetin.

5 mg (for once-a-day use)
Each yellow, almond-shaped, film-coated tablet, marked on one side with "C5", contains tadalafil 5 mg. Nonmedicinal ingredients: croscarmellose sodium, hydroxypropyl cellulose, hydroxypropyl methylcellulose, iron oxide, lactose monohydrate, magnesium stearate, microcrystalline cellulose, sodium lauryl sulfate, talc, titanium dioxide, and triacetin.

10 mg (for "on-demand" dosing)
Each yellow, almond-shaped, film-coated tablet, marked on one side with "C10", contains tadalafil 10 mg. Nonmedicinal ingredients: croscarmellose sodium, hydroxypropyl cellulose, hydroxypropyl methylcellulose, iron oxide, lactose monohydrate, magnesium stearate, microcrystalline cellulose, sodium lauryl sulfate, talc, titanium dioxide, and triacetin.

20 mg (for "on-demand" dosing)
Each yellow, almond-shaped, film-coated tablet, marked on one side with "C20", contains tadalafil 20 mg. Nonmedicinal ingredients: croscarmellose sodium, hydroxypropyl cellulose, hydroxypropyl methylcellulose, iron oxide, lactose monohydrate, magnesium stearate, microcrystalline cellulose, sodium lauryl sulfate, talc, titanium dioxide, and triacetin.

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How should I use this medication?

For the treatment of erectile dysfunction:

On-demand dosing:

The usual recommended dose is 20 mg taken as needed, at least 30 minutes before sexual activity. This medication has been shown to be effective within 30 minutes of taking the tablet, and last up to 36 hours later. As the amount of time tadalafil takes to work varies from person to person, starting sexual activity at different times after taking the tablet will determine the optimal time for sexual activity. The maximum recommended amount of medication to take is one tablet a day.

Once-a-day use:

The usual recommended dose is 5 mg per day, taken at about the same time each day and regardless of when sexual activity is planned. The daily dose may be lowered by your doctor if necessary.

Tadalafil may be taken with or without food.

For the treatment of benign prostatic hyperplasia (BPH) or erectile dysfunction with BPH:

The usual recommended dose is 5 mg once daily, at about the same time each day. It may be taken with or without food.

Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important that this medication be taken exactly as prescribed by your doctor. Do not take higher doses of this medication than prescribed by your doctor. Contact your doctor if you take a greater dose of tadalafil than prescribed.

Store this medication at room temperature (between 15°C and 30°C) and keep it out of the reach and sight of children.

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

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Who should NOT take this medication?

Do not take tadalafil if you:

  • are allergic to tadalafil or any ingredients of this medication
  • have had vision loss caused by an eye condition called nonarteritic anterior ischemic optic neuropathy (NAION)
  • are taking the medication riociguat
  • are taking (or have taken in the past 48 hours) any type of nitrate medication in any form (oral, sublingual [under the tongue], skin patch, or spray). Nitrate medications include nitroglycerin and related medicines that are used for the relief of chest pain or angina. They also include amyl nitrite "poppers." Use of these medications with tadalafil could cause a sudden severe drop in blood pressure that could lead to dizziness, fainting, heart attack, or stroke.

Nitrates are found in medications that are used to treat angina (chest pain). If you are not sure if you are taking nitrates, ask your doctor or pharmacist. Nitrates must NOT be taken by anyone who is using tadalafil because they can cause your blood pressure to drop very low. This may cause dizziness, fainting, heart attack, or stroke.

What side effects are possible with this medication?

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

  • back pain
  • facial flushing
  • headache
  • indigestion or stomach discomfort following meals
  • muscle ache
  • nasal congestion

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

  • dizziness
  • eye pain
  • high blood pressure
  • red eyes
  • swollen eyelids

Stop taking the medication and seek immediate medical attention if any of the following occur:

  • an allergic reaction (e.g., rash; itching; shortness of breath; swollen face, lips, or throat)
  • chest pains, an irregular heartbeat, or shortness of breath when starting sexual activity (if you have a heart condition)
  • hearing loss
  • prolonged (longer than 4 hours), painful, or inappropriate erection of penis
  • temporary memory loss
  • vision changes, including partial or total loss of vision

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Are there any other precautions or warnings for this medication?

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Alcohol: Consumption of alcohol may decrease the ability to achieve an erection and may also temporarily decrease blood pressure, causing dizziness and fainting.

Blood pressure: Tell your doctor if you are taking medications to treat high blood pressure. The combination of these medications with tadalafil may add to the blood-pressure-lowering effect of these medications. This may lead to dizziness or fainting.

Grapefruit juice: Grapefruit juice can increase the amount of tadalafil in your blood. Do not drink grapefruit juice when taking this medication.

Hearing problems: Rarely, people taking tadalafil have experienced a sudden decrease or loss of hearing. If this occurs, you should seek medical attention immediately.

Heart conditions: Speak to your doctor before taking any medication for erectile dysfunction if you:

  • have, or have had, heart disease
  • have had a heart attack
  • have had a stroke
  • have angina (chest pain as a result of poor blood flow to the heart muscle)
  • have experienced chest pain during sexual activity
  • have uncontrolled irregular heart rhythm
  • have very low blood pressure
  • have uncontrolled high blood pressure

If you experience chest pains, dizziness, or nausea during sex, stop the exertion, and inform your doctor as soon as you can.

Kidney function: Kidney disease or reduced kidney function may cause this medication to build up in the body, causing side effects. Lower doses of this medication should be used if you have impaired kidney function. Daily use of "on-demand" medication is not recommended. It should not be used more than 3 times per week. Once-a-day use with 5 mg dosing or less may be considered for some people with mild-to-moderate kidney problems.

Liver function: Liver disease or reduced liver function may cause this medication to build up in the body, causing side effects. Men with poor liver function may need lower doses of this medication. Daily use of this medication is not recommended. It should not be used more frequently than 3 times per week. Once-a-day use with 5 mg dosing or less may be considered for some patients with liver problems.

Nitrate-containing medications: Tadalafil should never be taken with any medications that contain nitrates. Blood pressure may drop to life-threatening levels if tadalafil is taken with any nitrate-containing medication (e.g., nitroglycerin tablets, spray, or patches) or any other nitrates (e.g., isosorbide dinitrate or amyl nitrite "poppers"). Dizziness, fainting spells, heart attack, or stroke may be experienced.

If use of a nitrate-containing medication is considered medically necessary, 48 hours must pass after the last dose of tadalafil before taking a nitrate, and only under close medical supervision.

Penis deformation: As with other medications for erectile dysfunction, men with an anatomical deformation of the penis such as angulation, cavernosal fibrosis, or Peyronie's disease should be closely monitored by their doctors if they take this medication. If you have any of these conditions, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Prolonged erection (priapism): If an erection lasts longer than 4 hours (a rare occurrence), seek immediate medical assistance. If this condition is not treated quickly, tissue damage and permanent loss of the ability to have an erection could result.

Tell your doctor if you have any of the following conditions, as they may increase your risk of a prolonged erection: sickle cell anemia, multiple myeloma, or leukemia.

Prostate problems: If you are taking other medications to treat BPH called alpha blockers (e.g., doxazosin), let your doctor know. The combination of alpha blockers with tadalafil is not recommended for treatment of BPH. People who are taking tadalafil for erectile dysfunction may be able to continue taking alpha blockers. Talk to your doctor for more information.

Vision problems: If you experience a sudden loss of vision in one or both eyes, or other vision-related problems, contact your doctor immediately. Vision loss may be partial or complete. While in some cases the condition may improve over time, it can be permanent in other cases. This is a rare condition that more likely to occur if you have heart disease, high blood pressure, high cholesterol, diabetes, or eye problems, if you are more than 50 years old, or if you smoke.

Pregnancy and breast-feeding: Tadalafil is not intended for use by women.

Children and adolescents: Tadalafil is not intended for use by children or adolescents under 18 years old.

What other drugs could interact with this medication?

There may be an interaction between tadalafil and any of the following:

  • abiraterone
  • alcohol
  • alpha-blockers (e.g., alfuzosin, doxazosin, terazosin)
  • alprostadil
  • alpha agonists (e.g., clonidine, methyldopa)
  • amiodarone
  • angiotensin-converting enzyme inhibitors (ACEIs; captopril, enalapril, ramipril)
  • angiotensin receptor blockers (ARBs; e.g., candasartan, irbesartan, losartan)
  • antacids (magnesium hydroxide, aluminum hydroxide)
  • aprepitant
  • "azole" antifungals (e.g., itraconazole, ketoconazole, voriconazole)
  • beta-adrenergic blockers (e.g., atenolol, propranolol, sotalol)
  • bicalutamide
  • boceprevir
  • bosentan
  • calcium channel blockers (e.g., amlodipine, diltiazem, nifedipine, verapamil)
  • carbamazepine
  • clonidine
  • conivaptan
  • cyclosporine
  • desipramine
  • diuretics (water pills; e.g., furosemide, hydrochlorothiazide, triamterene)
  • enzalutamide
  • HIV non-nucleoside reverse transcriptase inhibitors (NNRTIs; e.g., delaviridine, efavirenz, etravirine, nevirapine)
  • HIV protease inhibitors (e.g., atazanavir, indinavir, ritonavir, saquinavir)
  • grapefruit juice
  • imatinib
  • ivacaftor
  • lomitapide
  • macrolide antibiotics (e.g., clarithromycin, erythromycin)
  • metronidazole
  • nitrates (e.g., nitroglycerin, isosorbide mononitrate, isosorbide dinitrate, or amyl nitrite "poppers")
  • norfloxacin
  • other medications for erectile dysfunction (e.g., sildenafil, vardenafil)
  • oxcarbazepine
  • phenobarbital
  • phenytoin
  • primidone
  • rifabutin
  • rifampin
  • riociguat
  • sertraline
  • simeprevir
  • stiripentol
  • tamsulosin
  • telaprevir
  • tetracycline
  • tipranavir

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

  • stop taking one of the medications,
  • change one of the medications to another,
  • change how you are taking one or both of the medications, or
  • leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications that you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.