Increased risk for the development of prostatic hyperplasia in older patients; perform regular exam of the prostate. Regularly monitor testosterone levels; Hb, haematocrit, liver function & blood lipid profile. Reports of venous thromboembolic events, including DVT & pulmonary embolism; benign & malignant liver tumors. Patients w/ thrombophilia; severe cardiac, hepatic, or renal insufficiency or ischaemic heart disease; pre-existing HTN. Can cause accelerated growth & bone maturation & premature epiphyseal closure in childn. Appearance of common acne. Pre-existing sleep apnea may be potentiated. Not for enhancing muscular development or increasing physical ability. Anaphylactic reactions. Concomitant use w/ coumarin-derived anticoagulants. May reversibly reduce spermatogenesis. Childn & adolescent (male) <18 yr. Elderly >65 yr.