Side Effects of Letrozole

When side effects of letrozole occur, they are usually minor and easily treated. Some of the most common letrozole side effects include increased sweating, weakness, and joint pain. However, a number of side effects with letrozole are more serious and should be reported immediately to a healthcare provider. Among these serious side effects are signs of a blood clot and an increase in tumor size or the appearance of new tumors.

Letrozole Drug Information

An Introduction to Side Effects of Letrozole

As with any medicine, side effects are possible with letrozole (Femara^®); however, not everyone who takes the medication will experience side effects. In fact, most people tolerate it quite well. When side effects do occur, in most cases they are minor and either require no treatment or are easily treated by you or your healthcare provider.

(This article covers many, but not all, of the possible side effects with letrozole. Your healthcare provider can discuss a more complete list of letrozole side effects with you.)

Common Side Effects of Letrozole

Letrozole has been studied thoroughly in clinical trials. In these studies, the side effects that occur in a group of people taking the drug are documented and are then compared to side effects that occur in another group of people not taking the medicine. In these studies, the most common side effects of letrozole included:

Hot flashes -- in up to 33.7 percent of women
Fatigue or weakness -- up to 33.6 percent
Increased sweating -- up to 24.2 percent
Joint pain or arthritis -- up to 22 percent
Headaches -- up to 20.1 percent
Swelling or water weight gain -- up to 18.4 percent
Back pain -- up to 18 percent
Nausea -- up to 17 percent
High cholesterol -- up to 15.6 percent (see Femara and High Cholesterol).

Some other common side effects (occurring in 2 percent to 15 percent of people) included:

Dizziness
Night sweats
Cough
Constipation
Weight loss
Weight gain (see Femara and Weight Gain)
Diarrhea
Vomiting
Insomnia (see Femara and Insomnia)
Breast pain
Muscle pain
The flu
Urinary tract infections (UTIs or bladder infections)
Broken bones
Vaginal dryness or irritation
Loss of appetite
Indigestion or heartburn
Drowsiness.

(Side Effects of Letrozole Continued: Page 2)