The Cialis brand of tadalafil is used in men to treat erectile dysfunction (impotence) and symptoms of benign prostatic hypertrophy (enlarged prostate).

Adcirca and Alyq are used in men and women to treat pulmonary arterial hypertension (PAH) and to improve exercise capacity.

Do not take Cialis for erectile dysfunction if you are taking Adcirca or Alyq for pulmonary arterial hypertension.

Alyq may also be used for purposes not listed in this medication guide.

Taking Alyq with certain other medicines can cause a sudden and serious decrease in blood pressure.

Do not take Alyq if you also use riociguat, or a nitrate drug such as nitroglycerin, isosorbide dinitrate, isosorbide mononitrate, or recreational drugs such as "poppers."

Get medical help at once if you have nausea, chest pain, or dizziness during sex.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

When taking Adcirca or Alyq, you may need 2 tablets for a full dose. Take both tablets one after the other. Do not split the dose.

Take Cialis just before sexual activity, but not more than once per day. Cialis can help achieve an erection when sexual stimulation occurs. An erection will not occur just by taking a pill.

Do not break or split a Cialis tablet. Swallow it whole.

Take the medicine at the same time each day, with or without food.

Do not change your Alyq dose or stop taking this medicine without your doctor's advice.

Store at room temperature away from moisture and heat.

You should not take Alyq if you are allergic to it, or:

• if you take other medicines to treat pulmonary arterial hypertension, such as riociguat (Adempas).

Do not take Alyq if you are also using a nitrate drug for chest pain or heart problems. This includes nitroglycerin, isosorbide dinitrate, and isosorbide mononitrate. Nitrates are also found in some recreational drugs such as amyl nitrate, butyl nitrate or nitrite ("poppers"). Taking this medicine with a nitrate medicine can cause a sudden and serious decrease in blood pressure.

Some Alyq can remain in your bloodstream for 2 or more days after each dose you take (longer if you have liver or kidney disease). Avoid nitrate use during this time.

Tell your doctor if you have ever had:

• heart problems (chest pain, a heart rhythm disorder, heart failure);

• a heart attack or stroke;

• high or low blood pressure;

• liver disease;

• kidney disease (or if you are on dialysis);

• retinitis pigmentosa (an inherited condition of the eye);

• blindness in one or both eyes;

• hearing problems;

• blood circulation problems;

• a blood cell disorder such as sickle cell anemia, multiple myeloma, or leukemia;

• pulmonary veno-occlusive disease (PVOD);

• a physical deformity of the penis (such as Peyronie's disease), or an erection lasting longer than 4 hours;

• a stomach ulcer; or

• health problems that make sexual activity unsafe.

A small number of people taking Alyq have had sudden vision loss. Most of these people already had eye problems, or had diabetes or other health conditions that can affect blood vessels in the eyes. It is not clear whether this medicine causes vision loss.

Do not start or stop taking Alyq during pregnancy without your doctor's advice. Having pulmonary arterial hypertension (PAH) during pregnancy may cause heart failure, stroke, or other medical problems in both mother and baby. Tell your doctor right away if you become pregnant.

It may not be safe to breastfeed while using Alyq. Ask your doctor about any risk.

Cialis is not for use in women.

Alyq is not approved for use by anyone younger than 18 years old.

Since Cialis is used as needed, you are not likely to miss a dose.

If you miss a dose of Adcirca or Alyq, take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Avoid drinking alcohol. It may increase your risk of dizziness or fainting.

Grapefruit may interact with Alyq and lead to unwanted side effects. Avoid the use of grapefruit products.

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Alyq may cause serious side effects. Stop using Alyq and call your doctor at once if you have:

• heart attack symptoms--chest pain or pressure, pain spreading to your jaw or shoulder, nausea, sweating;

• vision changes or sudden vision loss;

• ringing in your ears or sudden hearing loss; or

• an erection is painful or lasts longer than 4 hours (prolonged erection can damage the penis).

Stop and get medical help at once if you have nausea, chest pain, or dizziness during sex. You could be having a life-threatening side effect.

Common side effects of Alyq may include:

• headache;

• flushing (warmth, redness, or tingly feeling);

• nausea, upset stomach;

• runny or stuffy nose; or

• muscle pain, back pain, pain in your arms, legs, or back.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Do not take Cialis with similar medications such as avanafil (Stendra), sildenafil (Viagra) or vardenafil (Levitra). Tell your doctor about all other medications you use for erectile dysfunction.

Tell your doctor about all your other medicines, especially:

• medicines to treat erectile dysfunction or pulmonary arterial hypertension;

• drugs to treat high blood pressure or a prostate disorder;

• an antibiotic such as clarithromycin, erythromycin, rifampin, or telithromycin;

• antifungal medicine such as ketoconazole or itraconazole;

• medicine to treat HIV/AIDS, such as ritonavir and others; or

• seizure medicine such as carbamazepine or phenytoin.

This list is not complete. Other drugs may affect Alyq, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.