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1. Salt and Water Retention (see WARNINGS: Concomitant Use of an Adequate Diuretic is Required)-Temporary edema developed in 7% of patients who were not edematous at the start of therapy.
2. Pericarditis, Pericardial Effusion, and Tamponade (see WARNINGS).
3. Dermatologic-Hypertrichosis-Elongation, thickening, and enhanced pigmentation of fine body hair are seen in about 80% of patients taking minoxidil (minoxidil (minoxidil (minoxidil tablets) tablets) tablets) tablets. This develops within 3 to 6 weeks after starting therapy. It is usually first noticed on the temples, between the eyebrows, between the hairline and the eyebrows, or in the side-burn area of the upper lateral cheek, later extending to the back, arms, legs, and scalp. Upon discontinuation of minoxidil (minoxidil (minoxidil (minoxidil tablets) tablets) tablets) , new hair growth stops, but 1 to 6 months may be required for restoration to pretreatment appearance. No endocrine abnormalities have been found to explain the abnormal hair growth; thus, it is hypertrichosis without virilism. Hair growth is especially disturbing to children and women and such patients should be thoroughly informed about this effect before therapy with minoxidil (minoxidil (minoxidil (minoxidil tablets) tablets) tablets) is begun. Allergic-Rashes have been reported, including rare reports of bullous eruptions, and Stevens-Johnson Syndrome.
4. Hematologic-Thrombocytopenia and leukopenia (WBC < 3000/mm³) have rarely been reported.
5. Gastrointestinal-Nausea and/or vomiting has been reported. In clinical trials the incidence of nausea and vomiting associated with the underlying disease has shown a decrease from pretrial levels.
6. Miscellaneous-Breast tenderness-This developed in less than 1% of patients.
7. Altered Laboratory Findings-(a) ECG changes-Changes in direction and magnitude of the ECG T-waves occur in approximately 60% of patients treated with minoxidil (minoxidil (minoxidil (minoxidil tablets) tablets) tablets) . In rare instances a large negative amplitude of the T-wave may encroach upon the S-T segment, but the S-T segment is not independently altered. These changes usually disappear with continuance of treatment and revert to the pretreatment state if minoxidil (minoxidil (minoxidil (minoxidil tablets) tablets) tablets) is discontinued. No symptoms have been associated with these changes, nor have there been alterations in blood cell counts or in plasma enzymeconcentrations that would suggest myocardial damage. Long-term treatment of patients manifesting such changes has provided no evidence of deteriorating cardiac function. At present the changes appear to be nonspecific and without identifiable clinical significance. (b)-Effects of hemodilution-hematocrit, hemoglobin and erythrocyte count usually fall about 7% initially and then recover to pretreatment levels. (c) Other-Alkaline phosphatase increased varyingly without other evidence of liver or bone abnormality. Serum creatinine increased an average of 6% and BUN slightly more, but later declined to pretreatment levels.

See "Interaction with Guanethidine" under WARNINGS.

Last reviewed on RxList: 6/25/2008
This monograph has been modified to include the generic and brand name in many instances.