Serious adverse interactions between drugs continue to be reported. Many of these are due to inhibition or induction of cytochrome P450 (CYP) enzymes, particularly CYP3A4. CYP3A is thought to be involved in the metabolism of more than 50 percent of currently prescribed drugs.2 CYP3A4, which is more abundantly expressed than CYP3A5, accounts for most CYP3A activity in vivo.

The FDA has approved an extended-release (ER) capsule formulation of amantadine (Gocovri – Adamas) for once-daily treatment of levodopa-induced dyskinesia in patients with Parkinson's disease (PD). It is the first product to be approved in the US for this indication. Immediate-release (IR) amantadine has been used off-label for years to manage levodopa-induced dyskinesia.

The FDA has approved prabotulinumtoxinA-xvfs (Jeuveau – Evolus) for temporary improvement in the appearance of moderate to severe glabellar lines associated with corrugator and/or procerus muscle activity. Jeuveau is the fourth botulinum toxin product to be approved in the US for this indication (see Table 1). It has been available in South Korea as Nabota since 2014.

Cognitive behavioral therapy for insomnia (CBT-I) is recommended for initial treatment of chronic insomnia. CBT-I includes stimulus control, sleep education and hygiene, sleep restriction, relaxation training, and cognitive therapy. When CBT-I alone is not effective, pharmacologic treatment should be added.

Nadofaragene firadenovec-vncg (Adstiladrin – Ferring), an adenoviral vector-based gene therapy, has been approved by the FDA for treatment of adults with high-risk Bacillus Calmette-Guérin (BCG)-unresponsive non-muscle invasive bladder cancer (NMIBC) with carcinoma in situ with or without papillary tumors. It is the first adenoviral vector-based gene therapy to be approved in the US for this indication. The immune checkpoint inhibitor pembrolizumab (Keytruda) was approved for the same indication in 2021.

The FDA has approved an inhalation solution formulation of the long-acting antimuscarinic agent (LAMA) glycopyrrolate (Lonhala Magnair – Sunovion) for maintenance treatment of chronic obstructive pulmonary disease (COPD). The new formulation is delivered using a portable, handheld, electronic nebulizer. Glycopyrrolate is also available as a dry powder inhaler, both alone (Seebri Neohaler) and in combination with indacaterol (Utibron Neohaler), and as a metered-dose inhaler in combination with formoterol (Bevespi Aerosphere). Lonhala Magnair is the first nebulized LAMA to become...

Two combinations of an inhaled corticosteroid with an inhaled long-acting beta2-agonist are approved by the FDA for use in patients with COPD: fluticasone/salmeterol (Advair Diskus) and budesonide/formoterol (Symbicort). A Medical Letter reader has questioned the safety of using corticosteroid inhalers in patients with this disorder. No single-agent inhaled corticosteroid inhaler is approved for this indication.

Gastrointestinal gas may cause symptoms when excessive amounts become trapped in the stomach and intestinal tract. Simethicone (Gas-X, Maalox Anti-Gas, Mylanta Gas Relief, Mylicon, Phazyme), sold over-the-counter in capsules, tablets and infant drop formulations, is being heavily advertised to the public for symptomatic treatment of flatulence and gastric bloating. According to a recent press release, 'Phazyme works fast so people can continue living active lives and eating the foods they love without fear of embarrassment.' Products that combine one or more antacids with simethicone...

The FDA has approved incobotulinumtoxinA (Xeomin – Merz) for treatment of cervical dystonia and blepharospasm in adults. It has been commercially available in Germany since 2005. Several formulations of botulinum toxin type A (Botox; Dysport) and type B (Myobloc) are already marketed for treatment of cervical dystonia. Botox is also approved for treatment of blepharospasm.

The FDA has approved the opioid agonist hydromorphone in a once-daily extended-release (ER) oral tablet formulation (Exalgo – Covidien) for the management of moderate to severe pain in opioid-tolerant patients requiring continuous, long-term therapy. Another hydromorphone ER formulation (Palladone – Purdue) was available previously, but was withdrawn from the market because taking it with alcohol could interfere with the extended-release mechanism and lead to rapid release of potentially lethal amounts of the drug ("dose-dumping").