A relatively healthy forty-six-year-old woman with mild hypertension receives a prescription for an antihypertensive medication. One of the medication's adverse effects is its potential to cause severe depression. Four months later, she is diagnosed with anxiety, an early manifestation of depression. An antianxiety drug is prescribed, but her anxiety worsens. Her physician then diagnoses her as having a depressive disorder, and prescribes a new antidepressant medication. She is still on the same antihypertensive.

A seventy-two-year-old man is given furosemide and digoxin to control a mild case of congestive heart failure and hypertension. Because furosemide deletes potassium from the body, his physician also places him on a potassium supplement. Six months later, the physician tells the patient to stop taking the furosemide and prescribes an angiotensin converting enzyme (ACE) inhibitor. An effect of ACE inhibitors is to reduce the body's excretion of potassium thereby reducing the digoxin's effectiveness.