The FDA has approved the atypical antipsychotic pimavanserin (Nuplazid – Acadia) for treatment of hallucinations and delusions associated with Parkinson's disease. It is the first drug to be approved in the US for this indication.

Many drugs can cause psychiatric symptoms, but a causal connection is often difficult to establish. Psychiatric symptoms that emerge during drug treatment could also be due to the underlying illness, previously unrecognized psychopathology, or psychosocial factors. The withdrawal of some drugs can cause symptoms such as anxiety, psychosis, delirium, agitation or depression.

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Older patients are especially susceptible to drug-induced cognitive impairment. They are more likely to be taking multiple drugs, to have higher blood levels of those drugs because of renal or hepatic dysfunction, and to have pre-existing cognitive problems that make it difficult to detect the role of drugs causing new symptoms or making old ones worse.

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.

Three benzodiazepines and 16 other compounds are marketed in the USA for treatment of insomnia. Many authorities believe that insomnia is overdiagnosed and overtreated (MK Erman, ed, Sleep Disorders, Psychiatr Clin North Am, Volume 10, Dec 1987).

Methamphetamine, a highly addictive synthetic sympathomimetic, has again become important as a drug of abuse in the US. Its resurgence has been associated with unsafe sexual practices that have resulted in an increase in HIV transmission, particularly among men who have sex with men (SJ Semple et al, J Subst Abuse Treat 2002; 22:149; A Urbina and K Jones, Clin Infect Dis 2004; 38:890).

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.

The oral retinoid isotretinoin (Accutane, and others) is the most effective drug available for treatment of acne.1 The FDA has recently approved a new oral isotretinoin product (Absorica – Cipher/Ranbaxy) for treatment of severe, recalcitrant nodular acne.Isotretinoin can completely clear severe nodulocystic lesions, in some cases leading to remission that can persist for years after treatment is stopped. Mucocutaneous adverse effects include dry skin, dry eye, epistaxis, nasopharyngitis, cheilitis, alopecia, eczema, skin fragility and photosensitivity. Musculoskeletal symptoms,...

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.