The review, documentation, and management of side effects is an important part of pharmacologic treatment. The clinician should warn patients of the possibility of side effects and should review with them those that are common. A general rule of thumb is that any side effect that occurs in 5% or more of patients in clinical trials should be discussed. However, the clinician should address any serious adverse experience, even those that might be rare, and should warn the patient that other unusual effects may occur. For example, although hypothyroidism is an uncommon outcome of lithium treatment, patients should be warned of this possibility. The clinician should review and document side effects with each patient and undertake a plan to manage unacceptable effects. Most side effects will improve with time, but noncompliance may be the price of ongoing serious problems. Each patient has his or her own tolerance for side effects, and the patient's tolerance must be considered. For example, sexual side effects of drugs may be completely unimportant for some patients (especially those with no current sexual partner) but critical for others. Further, sexual side effects may be unimportant in one phase of treatment and monumental in others (e.g., when a new relationship is established).
Laboratory evaluations may be required to determine if certain serious reactions have occurred (e.g., hepatotoxicity or nephrotoxicity). Certain drugs require regular plasma-level monitoring to provide the patient with a margin of safety. Biweekly white blood counts are an absolute requirement for clozapine therapy, and annual or biannual thyroid-stimulating hormone and creatinine tests may be performed for patients on lithium. Proper medication management requires regularly scheduled laboratory evaluations for many patients.