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.

Ecamsule (terephthalylidene dicamphor sulfonic acid), the first new sunscreen agent to be approved by the FDA in 18 years, is now available in the US in a moisturizer called Anthelios SX. Ecamsule has been used in Canada and Europe for more than 10 years.

Many patients ask their healthcare providers whether they should take vitamins. Since the last Medical Letter article on this subject, more data have become available on the benefits and risks of taking vitamins.

The FDA has approved daridorexant (Quviviq – Idorsia), an orexin receptor antagonist, for treatment of sleep-onset and/or sleep-maintenance insomnia in adults. Daridorexant is the third orexin receptor antagonist to be approved for this indication; suvorexant (Belsomra) and lemborexant (Dayvigo) were approved earlier.

Two recombinant vaccines, Arexvy (GSK) and Abrysvo (Pfizer), have been approved by the FDA for prevention of lower respiratory tract disease (LRTD) caused by respiratory syncytial virus (RSV) in adults ≥60 years old. They are the first RSV vaccines to be approved in the US. Abrysvo is also approved for use in pregnant women at 32-36 weeks' gestation to prevent LRTD caused by RSV in their infants from birth through 6 months of age.

The drugs of choice for treatment of fungal infections are listed in the table that begins on page 62. Some of the indications and dosages recommended here have not been approved by the FDA. More detailed guidelines for some of these infections are available online from the Infectious Diseases Society of America (www.idsociety.org).

A selective serotonin reuptake inhibitor (SSRI) is generally used for initial treatment of major depressive disorder (MDD). A serotonin-norepinephrine reuptake inhibitor (SNRI), bupropion (Wellbutrin SR, and others), and mirtazapine (Remeron, and others) are reasonable alternatives. Improvement in symptoms can occur within the first two weeks of treatment with these drugs, but a substantial benefit may not be achieved for 4-8 weeks.

Initial treatment of allergic rhinitis (AR) depends on the severity of symptoms and whether they are intermittent or persistent (see Table 1).

Cannabis (marijuana) contains more than 60 pharmacologically active cannabinoids; delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) are the best known. THC is the main psychoactive constituent of cannabis. CBD, unlike THC, does not produce intoxication or euphoria.

The recommendations for treatment of varicella-zoster virus (VZV) and herpes simplex virus (HSV) infections are listed in tables 1 and 2. Vaccination against VZV was reviewed in a previous issue.