Opioid use disorder is a chronic, relapsing disease with physical and psychiatric components. It is associated with economic hardship, social isolation, incarceration, increased rates of blood-borne infections such as HIV and viral hepatitis, adverse pregnancy outcomes, and increased mortality. According to the NIH, there were 80,411 deaths involving an opioid in the US in 2021, more than in any previous year. Several guidelines on the management of opioid use disorder are available; all recommend maintenance pharmacotherapy as the standard of care.

The FDA has approved the monoamine oxidase type B (MAO-B) inhibitor safinamide (Xadago – US Worldmeds) as an adjunct to levodopa/carbidopa for management of "off" episodes in patients with Parkinson’s disease (PD). It is the first reversible MAO-B inhibitor to be approved for this indication. Selegiline (Eldepryl, and others) and rasagiline (Azilect, and generics), two irreversible MAO-B inhibitors, have been used alone and as adjuncts to levodopa/carbidopa for many years. Safinamide is not approved for use as monotherapy.

Five different selective serotonin reuptake inhibitors (SSRIs) are promoted for treatment of depression and a sixth (fluvoxamine) for use in obsessive compulsive disorder. Which one should we prescribe for our patients?

The FDA recently approved the monoamine oxidase inhibitor (MAOI) selegiline in a transdermal (patch) formulation (Emsam - Bristol-Myers Squibb/Somerset) for treatment of major depressive disorder. Selegiline is also available in an oral formulation (Eldepryl, and others) for treatment of Parkinson's disease.

The FDA has approved Namzaric (Forest), a fixed-dose combination of extended-release (ER) memantine (Namenda XR), an NMDA-receptor antagonist, and donepezil (Aricept, and generics), an acetylcholinesterase inhibitor, for treatment of moderate to severe Alzheimer's type dementia in patients previously stabilized on both drugs. The patent for Namenda has recently expired and generic formulations of memantine 5- and 10-mg tablets have been approved.

The FDA has approved fenfluramine oral solution (Fintepla – Zogenix) for treatment of seizures in patients ≥2 years old with Dravet syndrome. It is the third drug to be approved for this indication. Stiripentol (Diacomit) and cannabidiol (Epidiolex), a purified product derived from marijuana, were approved earlier.

Rasagiline (Azilect - Teva), a monoamine oxidase-type B (MAO-B) inhibitor, was recently approved by the FDA for once-daily oral treatment of Parkinson's disease (PD). It can be taken alone for treatment of early disease or with levodopa/carbidopa (Sinemet, and others) for advanced disease. Selegiline (Eldepryl, and others), the first MAO-B inhibitor marketed in the US, has been available since 1988; a new lower-dose disintegrating tablet (Zelapar) was recently approved.

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.