Cialis

If Cialis is taken with certain other drugs, the effects of either could be increased, decreased, or altered. It is especially important to check with your doctor before combining Cialis with the following:

Other impotence drugs including alprostadil (Caverject), sildenafil (Viagra), and vardenafil (Levitra)
Erythromycin (E-Mycin, Ery-Tab, PCE)
Grapefruit juice
Indinavir (Crixivan)
Itraconazole (Sporanox)
Ketoconazole (Nizoral)
Rifampin (Rifadin, Rimactane)
Ritonavir (Norvir)

It's best not to drink too much alcohol while you're taking Cialis. Combining the two could lower your blood pressure and cause dizziness, especially upon standing. Drinking five or more servings of alcohol could intensify this effect and also cause headache and rapid heartbeat.

Special information about pregnancy or breastfeeding

Cialis should not be used by women. Its effects during pregnancy and breastfeeding have not been studied.

Recommended dosage

ADULT MALES

Doses range from 5 milligrams to 20 milligrams, depending on the drug's effect. The recommended starting dose is 10 milligrams.

Take Cialis only before sexual activity. The manufacturer recommends a maximum of one dose per day. If you're taking certain drugs that affect the liver, such as ritonavir (Norvir) or ketoconazole (Nizoral), the maximum recommended dose is 10 milligrams no more than once every 3 days.

If you have moderate kidney impairment, the recommended starting dose is 5 milligrams once a day, up to a maximum of 10 milligrams once every 2 days. If you have severe kidney impairment or need dialysis, the maximum recommended dose is 5 milligrams once a day. No dosage adjustment is required if you have mild kidney problems.

If you have mild or moderate liver impairment, your total daily dose should not exceed 10 milligrams once a day. If your liver is severely impaired, you will not be able to use Cialis.

Overdosage

Large doses of Cialis (up to 500 milligrams) resulted in similar side effects as regular doses. However, any medication taken in excess can have serious consequences. If you suspect an overdose, seek medical attention immediately.