See also Warnings.Diarrhea, excitation, or trouble sleeping may occur. If any of these effects persist or worsen, notify your doctor or pharmacist promptly.Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.Tell your doctor immediately if any of these serious side effects occur: mental/mood changes, swelling of the ankles/feet, unusual or rapid weight gain, trouble breathing, decreased/increased interest in sex, new or worsening acne.Males before puberty - tell your doctor immediately if any of these signs of maturation occur while taking this drug: enlargement of the penis, more frequent erections.Adult males - tell your doctor immediately if any of these serious side effects occur: hair loss, trouble urinating, changes in testicle size, impotence, breast tenderness/swelling.For males, in the very unlikely event you have a painful or prolonged erection lasting 4 or more hours, stop using this drug and seek immediate medical attention, or permanent problems could occur.Females (both young girls and women) may experience signs of masculinization. These changes may be irreversible. Discuss the risks and benefits of therapy with your doctor. Seek immediate medical attention if the following serious side effects occur: deepening of the voice/hoarseness, facial hair growth, new or worsening acne, clitoral enlargement, menstrual period changes.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.