Table 1.
Classification and definition | Subtype | Example |
---|---|---|
Adverse drug reaction | ||
A medical problem resulting from an adverse effect of a drug. These include sensitivities, intolerances, and immune-mediated hypersensitivity reactions. | Minor | Minor dizziness related to propranolol; manage with lifestyle counseling. |
Moderate | Gynecomastia related to spironolactone; may require dose adjustment or cessation. | |
Severe | Stevens-Johnson syndrome precipitated by sulfamethoxazole-trimethoprim (Bactrim DS®). | |
Drug interactions | ||
An actual or potential medical problem that is related to a drug-drug or drug-patient interaction. | Drug-drug | Harvoni® (Gilead Sciences, Foster City, CA, USA) and amiodarone. |
Drug-patient | Hepatorenal syndrome precipitated by NSAID use. | |
Drug use without indication | ||
The patient is taking a medication for no medically valid reason. | Proton pump inhibitor use in a patient without gastroesophageal reflux disease, peptic ulcer, or variceal bleeding. | |
Incorrect dosage | ||
A medical condition that is being treated with drug therapy; however, the dose may be too low or too high. | Subtherapeutic | 10-ml daily dose of lactulose, achieving one bowel motion every second day. |
Supratherapeutic | Spironolactone 400 mg daily in a patient with minimal abdominal ascites. | |
Nonadherence | ||
The patient is prescribed a drug for a medical condition but is not taking it for psychological, sociological, or economic reasons. | Unintentional | Forgetting to take propranolol at nighttime. |
Intentional | Not taking lactulose because of side effects (flatulence, bloating) or cost following removal from the Pharmaceutical Benefits Scheme. | |
Untreated indications | ||
A medical condition that requires drug therapy but is not being treated with medication. This may be related to intentional or unintentional nonadherence by the patient, or to intentional or unintentional underprescribing by a medical practitioner. | Nonadherence | As above. |
Underprescribing | Low cholecalciferol and tocopherol identified by pathology, not supplemented. Unintentional – oversight. Intentional – patient unable to afford currently; to be reconsidered at next visit. |
NSAID Nonsteroidal anti-inflammatory drug