The FDA has approved the marketing of RotaShield, a live oral vaccine for prevention of infantile rotavirus infection. Rotaviruses are segmented double-stranded RNA viruses that are the most common cause of severe diarrhea and dehydration in infants and young children.

The oral fixed-dose combination of the neprilysin inhibitor sacubitril and the angiotensin receptor blocker (ARB) valsartan (Entresto – Novartis) was approved in 2015 to reduce the risk of cardiovascular death and hospitalization for heart failure in adults with chronic heart failure (NYHA Class II-IV) and reduced ejection fraction (HFrEF; LVEF...

The FDA has restricted its Emergency Use Authorization for the adenovirus-based COVID-19 vaccine manufactured by Johnson & Johnson (Janssen) to adults who are unable or unwilling to receive another COVID-19 vaccine. The mRNA COVID-19 vaccines manufactured by Pfizer/BioNTech (Comirnaty) and Moderna (Spikevax) are preferred for all persons without a contraindication.

The FDA has approved the over-the-counter (OTC) sale of Narcan (Emergent), a nasal spray that delivers 4 mg of the opioid antagonist naloxone. Narcan nasal spray has been available by prescription since 2015 for emergency treatment of opioid overdose. Generic formulations of Narcan have also been approved; the manufacturers of these products will be required to switch them to OTC status and amend their labeling accordingly. Kloxxado, an 8-mg naloxone nasal spray, remains available only by prescription.

The amyloid beta-directed monoclonal antibody lecanemab-irmb (Leqembi – Eisai/Biogen) has now been approved by the FDA for once-monthly use for treatment of Alzheimer's disease (AD) in patients with mild cognitive impairment (MCI) or mild dementia. It was previously approved only for administration once every 2 weeks. Now, lecanemab can be given every 4 weeks after an 18-month initiation phase of biweekly administration.

The FDA has approved a 12.5-mg tablet formulation of the thiazide-like diuretic chlorthalidone (HemiClor – Ingenus) for treatment of hypertension. Chlorthalidone has been available for years in 15-, 25-, and 50-mg tablets (Thalitone, and generics) and in fixed-dose combinations with azilsartan medoxomil (Edarbyclor) and atenolol (Tenoretic, and generics).

The text that follows reviews some common bacterial infections and their empiric treatment pending the results of culture and susceptibility testing. The recommendations made here are based on the results of susceptibility studies, clinical trials, and the opinions of Medical Letter reviewers. Tables 1 and 2 list the usual dosages of antibacterial drugs.

The Advisory Committee on Immunization Practices (ACIP) recommends use of certain vaccines in adults residing in the US. Routine childhood immunization has reduced the overall incidence of some of these vaccine-preventable diseases, but many adults remain susceptible. Recommendations for vaccination against COVID-19, seasonal influenza, and monkeypox and vaccination of travelers have been reviewed separately.

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.

Antimicrobial prophylaxis can decrease the incidence of postoperative surgical site infection after some procedures. Since the last Medical Letter article on this subject, consensus guidelines have been published. Recommendations for prophylaxis in specific surgical procedures are listed in Table 1.