Periodic evaluations of cardiovascular, hematologic, hepatic, and renal function are recommended for all patients who are receiving long-term levodopa pharmacotherapy. Collaboration with the patient’s advanced practice nurse or family physician is required. Levodopa pharmacotherapy in combination with peripheral decarboxylase inhibitor (e.g., benserazide, carbidopa) pharmacotherapy allows the dosage of levodopa to be decreased significantly. However, levodopa, the levorotatory isomer of dopa and the metabolic precursor of dopamine, does cross the blood–brain barrier. Levodopa is converted to dopamine in the basal ganglia. Extensive amounts of an oral dose of levodopa are metabolized in the lumen of the stomach and the small intestines. Levodopa pharmacotherapy has been associated with postural (orthostatic) hypotension. Therefore, concurrent pharmacotherapy with antihypertensives will require careful blood pressure monitoring and a possible reduction of the dosage of the antihypertensive.