Gynecomastia is the abnormal growth of breast glandular tissue in males and is distinctly different from fat deposition. It can occur in brief phases during infancy and puberty, and also in people who are middle-aged or elderly. Potentially treatable causes include tumors and hormonal, kidney, liver or thyroid dysfunctions. In about 10 to 25 percent of cases, medications and drugs are the cause. If the medication is stopped within one year, the changes can be reversible.
Hormones and Anti-Androgens
Males can get gynecomastia from medications when there is a disruption in the balance of estrogen and androgen in the body. This can occur when males take estrogen or human growth hormone, or when anabolic steroids are abused. This imbalance can also occur when medications are used to block androgens in the treatment of prostate cancer; these are called anti-androgens and cause gynecomastia in at least 10 percent of patients, according to the Merck Manual. Other medications, such as dutasteride and finasteride, which are used to shrink an enlarged prostate, reduce the production of androgens and cause breast growth in less than 1 percent of cases.
Gastrointestinal Drugs
Common medications that are used to treat heartburn and ulcers can cause gynecomastia because of their anti-androgen effect. This occurs in less than 4 percent of patients with cimetidine, and rarely with ranitidine and omeprazole.
CNS Drugs and Recreational Drugs
Some drugs can cause an increase in the levels of prolactin in the brain, leading to gynecomastia. According to a 2006 article in "Pharmacotherapy," the antipsychotic drugs haloperidol and risperidone have this effect. Methodone, which is used to treat chronic pain and narcotic withdrawal, can cause an elevation of prolactin, resulting in male breast growth. Diazepam, used to treat anxiety disorders and for sedation during medical procedures, can cause gynecomastia. Other drugs, like alcohol, amphetamines, heroin and marijuana can decrease testosterone levels and cause breast growth in males.
Cardiovascular Drugs
ACE inhibitors such as captopril and enalapril are used to treat high blood pressure and can infrequently cause gynecomastia. Calcium channel blockers, like nifedipine and diltiazem, are often used in the treatment of angina, blood pressure, or rhythm disturbances, and rarely cause male breast growth. Amiodarone is a medication used to treat cardiac arrhythmias that in rare cases causes male breast growth. Spironolactone is a diuretic used in conditions associated with lower leg swelling, such as heart failure and liver and adrenal diseases. Because of its anti-androgen properties, gynecomastia occurs in up to 9 percent of patients.
Herbals
In a 2007 study published in the "New England Journal of Medicine," the topical use of soaps and lotions that contained lavender and tea tree oils were found to cause reversible gynecomastia in prepubescent boys.
Anti-Neoplastics
This class includes drugs that have, in rare instances, caused gynecomastia and includes imatinib, used to treat cancer, and methotrexate, which is used for cancer, psoriasis, and rheumatoid arthritis treatment.
Antibiotics
Several medications used to treat infections can cause gynecomastia, including the anti-fungal ketoconazole and the anti-tuberculosis drug isoniazid. Metronizadole is a medication used to treat infections of the skin, bone, joint, brain and vaginal and gastrointestinal systems and can also cause breast growth.
HAART
Highly active antiretroviral therapy (HAART) has improved the prognosis for people with HIV, but is associated with many side effects. There is evidence that some of these drugs, specifically efavirenz, may also cause gynecomastia.
References
- Merck: Gynecomastia
- Up to Date: Gynecomastia
- NIH News: Lavender and Tea Tree Oils May Cause Breast Growth in Boys
- "Breast Journal": Efavirenz-Associated Gynecomastia: Report of Five Cases and Review of the Literature
- "Pharmacotherapy"; Atypical Antipsychotics and Pituitary Tumors: A Pharmacovigilance Study; Szarfman A et al.; June 2006
