View the Comparison Table: Drugs for Parkinson's Disease

The motor symptoms of Parkinson's disease (PD) are caused primarily by degeneration of dopaminergic neurons in the substantia nigra. The nonmotor symptoms of the disease are thought to be caused by degeneration of other neurotransmitter systems. No disease-modifying drugs are available for treatment of PD.

Most patients with multiple sclerosis (MS) present with the relapsing-remitting form of the disease. Pharmacologic treatment usually includes a disease-modifying drug, corticosteroids for acute exacerbations, and other drugs for managing symptoms such as fatigue, depression, and pain. Early use of disease-modifying therapy has improved clinical outcomes.

Anticoagulants are the drugs of choice for treatment and prevention of deep venous thrombosis (DVT) and pulmonary embolism (PE), collectively referred to as venous thromboembolism (VTE). US guidelines for treatment of VTE were updated in 2020 and 2021.

Irritable bowel syndrome (IBS) is a common disorder characterized by recurrent abdominal pain and altered bowel habits, often accompanied by bloating. IBS is classified by its predominant bowel symptom: constipation (IBS-C), diarrhea (IBS-D), mixed type (IBS-M), or unclassified (IBS-U). Since the exact cause of IBS is unknown, the goal of treatment is symptom control. Some over-the-counter (OTC) products and prescription drugs for IBS are listed in Tables 1-4. The safety of these drugs during pregnancy and lactation is described in Table 5 (online only).