A Review of Two More Drugs For Erectile Dysfunction: Vardenafil (LEVITRA) And Tadalifil (CIALIS)

Vardenafil (LEVITRA) and tadalafil (CIALIS) join sildenafil (VIAGRA) as the second and third oral drugs approved by the Food and Drug Administration to treat erectile dysfunction.

All three drugs work the same way by inhibiting an enzyme known as phosphodiesterase type 5. Inhibition of this enzyme causes relaxation of smooth muscles and increased blood flow to the penis.

Many commonly used drugs can interfere with sexual function in both men and women, causing loss of libido, or can interfere with erection or ejaculation in men, or can delay or prevent orgasm in women. Drug-related adverse effects on sexual function may be difficult to distinguish from the effects of depression or disease, but most are reversible when drug use is stopped and sometimes when dosage is decreased. On this page, there is a list of 130 drugs that can cause sexual dysfunction.

Before deciding to use vardenafil, tadalafil, or sildenafil, have a thorough check-up to rule out any medical problems that could cause a correctable sexual dysfunction. Also, check the list of drugs that can cause sexual dysfunction accompanying this article, and if you are taking any of them ask your doctor if they are still needed at all, if the dosage can be reduced, or ask about alternative drugs that do not cause sexual dysfunction.

None of these drugs should be used in combination with the family of drugs known as nitrates, such as nitroglycerine, which are used to treat chest pain (angina). Using nitrates with vardenafil, tadalafil, or sildenafil can result in dizziness, fainting, or a heart attack or stroke. Below is a list of nitrate drugs that can interact with vardenafil, tadalafil, or sildenafil.

In general, vardenafil, tadalafil, and sildenafil also should not be used in combination with the alpha-blocker family of drugs which are used to treat high blood pressure and enlarged prostate (benign prostatic hyperplasia). These drugs include alfuzosin (UROXATRAL), doxazosin (CARDURA), prazosin (MINIPRESS) tamsulosin (FLOMAX), and terazosin (HYTRIN). Using alpha-blockers with these three erectile dysfunction drugs can cause a dangerously low blood pressure that could lead ultimately to a stroke or heart attack.

The professional product labeling, or package insert, for tadalafil says not to take the drug with alpha blockers other than tamsulosin. The professional labeling for sildenafil says that the drug should not be taken in a dose greater than 25 milligrams at the same time (within four hours) of a dose of any alpha blocker. We advise consumers to be more cautious than this and avoid these erectile dysfunction drugs if they are taking an alpha blocker.

A number of drugs can interact with vardenafil, tadalafil, and sildenafil to increase the amounts of the erectile dysfunction drugs in the body. These include erythromycin (ERYTHROCIN, EES), indinavir (CRIXIVAN), itraconazole (SPORANOX), ketoconazole (NIZORAL), and ritonavir (NORVIR). In addition, interactions are listed for grapefruit juice with tadalafil and for sildenafil with cimetidine (TAGAMET) in their respective professional product labeling.

There are a number of medical conditions in which vardenafil, tadalafil, and sildenafil should be used with caution, or not at all, because of the potential for an adverse outcome. These are:

• heart problems such as angina, heart failure, irregular heartbeats, or a heart attack. Ask your doctor if it is safe for you to have sexual activity.
• low blood pressure or high blood pressure that is not controlled
• a stroke
• liver problems
• kidney problems or require dialysis
• retinitis pigmentosa, a rare genetic (runs in families) eye disease
• stomach ulcers
• a bleeding problem, a deformed penis shape, or Peyronie’s disease
• an erection that lasted more than 4 hours
• blood cell problems such as sickle cell anemia, multiple myeloma, or leukemia

Vardenafil is unique among these three drugs in that there are precautions in the drug’s professional product labeling about a condition known as QT_c interval prolongation. This is an abnormality in the heart’s electrical conduction that can lead to fatal heart rhythm disturbances.

The QT interval is the length of time it takes the ventricles (large chambers of the heart) to discharge and recharge electrically. The QT_c interval is measured on an electrocardiogram (EKG or ECG) in milliseconds (msec); the subscript “c” indicates that the QT interval has been corrected for the patient’s heart rate. Prolongation of the QT interval can lead to heart rhythm disturbances (cardiac arrhythmias) such as torsade de pointes. Torsade de pointes is a French phrase that means “twisted point” and describes the appearance of this type of rhythm disturbance on the EKG tracing.

Men with congenital QT prolongation and those taking drugs for heart rhythm disturbances such as amiodarone (CORDARONE), procainamide (PROCANBID), quinidine (DURAQUIN, QUINAGLUTE DURA-TABS, QUNIDEX), and sotalol (BETAPACE) should not take vardenafil.

There are legitimate reasons for using the erectile dysfunction drugs when other causes of erectile dysfunction have been ruled out. However, when these drugs are used for recreational purposes by men who do not need them, the risks of the drugs always outweigh the benefits.

What You Can Do

Do not use vardenafil, tadalafil, or sildenafil with any of the interacting drugs listed above.

Before deciding to use any of these drugs, have a thorough medical check-up to rule out any medical problems that could cause a correctable sexual dysfunction. Also, check the list of drugs that can cause sexual dysfunction in both men and women and if you are taking any of them ask your doctor if they are still needed, if the dosage can be reduced, or ask about alternative drugs that do not cause sexual dysfunction.