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.

The FDA has approved Cobenfy (BMS), an oral fixed-dose combination of the muscarinic agonist xanomeline and the peripheral muscarinic antagonist trospium chloride, for treatment of schizophrenia in adults. It is the first antipsychotic drug to be approved in the US for treatment of schizophrenia that does not block dopamine receptors. This is the first approval for xanomeline; trospium has been available for many years for treatment of overactive bladder.

The FDA has approved Crexont (Amneal), an extended-release capsule formulation of carbidopa/levodopa, for treatment of Parkinson's disease (PD), postencephalitic parkinsonism, and parkinsonism associated with carbon monoxide or manganese intoxication. Crexont contains a combination of immediate-release carbidopa/levodopa granules and extended-release levodopa pellets. An extended-release carbidopa/levodopa oral capsule (Rytary) has been available from the same manufacturer for years; the patent for Rytary expires in 2025.

View the Comparison Table: Drugs for Parkinson's Disease

A transdermal formulation of the second-generation (atypical) antipsychotic asenapine (Secuado – Noven) has been approved by the FDA for once-daily treatment of schizophrenia in adults. Asenapine is the first antipsychotic to become available in a transdermal formulation in the US. A twice-daily sublingual tablet formulation of asenapine (Saphris) has been available since 2009.

Three extended-release injectable formulations of second-generation antipsychotic drugs — two of risperidone (Rykindo, Uzedy) and one of aripiprazole (Abilify Asimtufii) — have been approved by the FDA for treatment of schizophrenia in adults. Rykindo and Abilify Asimtufii are also approved for maintenance treatment of bipolar I disorder in adults. Other extended-release injectable formulations of risperidone and aripiprazole have been available in the US for years (see Table 1).

Alzheimer's disease (AD) is the most common cause of dementia, but cognitive decline is also associated with other neurological conditions such as Parkinson's disease, dementia with Lewy bodies, vascular dementia, and frontotemporal dementia.

The oral second-generation antipsychotic drug lumateperone (Caplyta – Intra-Cellular Therapies), which was approved by the FDA in 2020 for treatment of schizophrenia, is now approved for use as monotherapy or as an adjunct to lithium or valproate for treatment of depressive episodes associated with bipolar I or II disorder in adults.

The FDA has approved a dextroamphetamine transdermal patch (Xelstrym – Noven) for once-daily treatment of attention-deficit/hyperactivity disorder (ADHD) in patients ≥6 years old. Xelstrym is the first transdermal amphetamine product to be approved in the US. A methylphenidate transdermal patch (Daytrana, and generics) has been available for years for treatment of ADHD.

The FDA has approved a sublingual fi lm formulation of the nonergot dopamine agonist apomorphine (Kynmobi – Sunovion) for acute, intermittent treatment of "off" episodes in patients with Parkinson's disease (PD). A subcutaneous formulation of apomorphine (Apokyn) has been available for years for the same indication in patients with advanced PD.