antidepressant: any of a class of drugs used to treat depression; often have undesirable side effects
medicine: (medicine) something that treats or prevents or alleviates the symptoms of disease
metoprolol: beta blocker (trade name Lopressor) used in treating hypertension and angina and arrhythmia and acute myocardial infarction; has adverse side effects (depression and exacerbation of congestive heart failure etc.)