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Treatments > Medications Used In MS

Brand Name Chemical Name

Cialis (U.S.)

Tadalafil (tah-DAL-a-fil)

Primary Usage in MS

Generic Available
Erectile dysfunction No

Tadalafil belongs to a group of medicines that delay the action of enzymes called phosphodiesterases that can interfere with erectile function. Tadalafil is used to treat men with erectile dysfunction (also called sexual impotence) because it helps to maintain an erection that has been created by stimulation. Tadalafil will not cause an erection without stimulation of the penis. Tadalafil is not indicated for use in women.

Proper Usage
Tadalafil, which may be taken up to once per day by most men, remains effective for up to 36 hours.

Tadalafil is available by prescription and should be used only as directed by your physician. The dose of this medication will be different for different patients. Do not take more of this medication than has been prescribed for you.

If you are older than 65 or have liver problems, your doctor may start you on a lower dose of this medication.

Tadalafil can interact with, or interfere with the action of, other medications you may be taking. Be sure to inform your physician of all other medications you are taking so that appropriate substitutions or dosage adjustments can be made. Tadalafil should not be used by men who are using: nitrates such as nitroglycerin (e.g., Nitrostat or Transderm-Nitro) to lower blood pressure; alpha blockers (e.g., Hytrin, Flomax, or Cardura) to treat prostate problems or high blood pressure. Tadalafil in combination with these medications can cause the blood pressure to drop too far.

The presence of certain medical problems can interfere with the use of tadalafil. Be sure to inform your doctor if you have any of the following medical problems: an abnormality of the penis (including a curved penis or birth defect); bleeding problems; retinitis pigmentosa; any conditions causing thickened blood or slower blood flow (e.g., leukemia, multiple myeloma, polycythemia, sickle cell disease, or thrombocycemia); a history of priapism (erection lasting longer than six hours); heart or blood disease; severe kidney problems; severe liver problems.

Tadalafil has not been studied in combination with other medications that are used in the treatment of erectile dysfunction. At the present time, it is not recommended that these drugs be used together.

Possible Side Effects
Side effects that you should report to your physician so that he or she can adjust the dosage or change the medication: flushing; headache; nasal congestion, stomach discomfort after meals; diarrhea.

Rare side effects that should be discussed with your physician: abnormal vision (e.g., blurred vision, seeing shades of colors differently than before, sensitivity to light); sudden decrease or loss of hearing; bladder pain; cloudy or bloody urine; dizziness, increased frequency of urination; painful urination.

Medication Index

Other Medications Used to Treat Erectile Dysfunction

About Sexuality

MS and Intimacy
Managing sexual problems, communication tips, resources, and more.

Reprinted with permission from Rosalind C. Kalb (ed.), Multiple Sclerosis: The Questions You Have—The Answers You Need (4th ed.). New York: Demos Medical Publishing, 2007.

Last updated October 19, 2007