A lidocaine 1.8% patch (ZTlido – Scilex) has been approved by the FDA for treatment of pain associated with postherpetic neuralgia (PHN). A lidocaine 5% patch (Lidoderm, and generics) was approved earlier for the same indication and has been used off-label for treatment of other types of localized pain. Both of these patches are available only by prescription. Lidocaine 4% patches (Aspercreme, IcyHot, and others) are available over the counter for back, neck, shoulder, and joint pain.

The FDA has approved a topical 8% patch formulation of capsaicin (Qutenza – NeurogesX), available only by prescription, for local treatment of postherpetic neuralgia. Postherpetic neuralgia occurs after herpes zoster in about one third of patients ≥60 years old and can persist for months or even years.

Difelikefalin (Korsuva – Vifor), an IV kappa opioid receptor (KOR) agonist, has been approved by the FDA for treatment of moderate to severe pruritus associated with chronic kidney disease (CKD) in adults on hemodialysis. It is the first drug to be approved for this indication and the first KOR agonist to become available in the US. Difelikefalin has not been studied in patients on peritoneal dialysis.

Fezolinetant (Veozah – Astellas), a first-in-class neurokinin 3 (NK3) receptor antagonist, has been approved by the FDA for treatment of moderate to severe vasomotor symptoms (VMS) due to menopause. It is the second nonhormonal treatment to be approved in the US for this indication; a low-dose formulation of the selective serotonin reuptake inhibitor (SSRI) paroxetine mesylate (Brisdelle) was approved in 2013.

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.

Duloxetine hydrochloride (Cymbalta - Lilly), a selective serotonin and norepinephrine reuptake inhibitor (SNRI) available for treatment of depression, has also been approved by the FDA for treatment of neuropathic pain associated with diabetic peripheral neuropathy (DPN). Duloxetine is one of two drugs approved specifically for management of neuropathic pain due to diabetes; the other, pregabalin (Lyrica - Pfizer), will be marketed soon and will be reviewed in the next issue of The Medical Letter.

The FDA has approved ezogabine (ee-ZOE-ga-been; Potiga – GSK/Valeant) for oral adjunctive treatment of partial-onset seizures in adults. Ezogabine is available in Europe as retigabine (Trobalt).

The FDA has approved lacosamide (Vimpat - UCB Pharma) for oral or intravenous (IV) use as add-on therapy in adults with partial-onset seizures.

The FDA has approved vigabatrin (vye gá ba trin; Sabril – Lundbeck) for oral use as add-on therapy for complex partial seizures in adults who are refractory to several antiepileptic drugs and as monotherapy for infantile spasms. Vigabatrin has been available in other countries for many years. Because of its potential for retinal toxicity, it will be available in the US only through a restricted distribution program called SHARE (Support, Help and Resources for Epilepsy). Prescribers and pharmacists distributing the drug must register, and patients must undergo visual field testing.

The primary symptoms of menopause are genitourinary and vasomotor. The genitourinary syndrome of menopause (GSM) includes symptoms such as burning, irritation, dryness, dyspareunia, dysuria, and recurrent urinary tract infection. Vasomotor symptoms (VMS; hot flashes, night sweats) often disrupt sleep.