1
Ensitrelvir (Xocova) for Post-Exposure Prophylaxis of COVID-19
The Medical Letter on Drugs and Therapeutics • July 20, 2026; (Issue 1759)
The FDA has approved ensitrelvir (Xocova – Shionogi), a SARS-CoV-2 main protease inhibitor, for postexposure prophylaxis
of COVID-19 in patients ≥12 years old who had contact with
an infected individual. Ensitrelvir is the first oral antiviral
drug to be approved in the US for this indication. The parenteral
monoclonal antibody combinations bamlanivimab and
etesevimab and casirivimab and imdevimab (REGEN-COV)
are no longer authorized for postexposure prophylaxis of
COVID-19 in the US.
2
Treatment of Common Respiratory Tract Infections
The Medical Letter on Drugs and Therapeutics • April 17, 2023; (Issue 1674)
Most respiratory tract infections are caused by
viruses. Bacterial respiratory tract infections are
usually treated empirically with antibiotic therapy
that targets the most probable causative pathogens.
Recommended antibiotic regimens for outpatient
treatment of some common respiratory tract
infections are listed in Table 1 for adults and Table 2
for children.
3
OTC Differin Epiduo Gel for Acne
The Medical Letter on Drugs and Therapeutics • July 20, 2026; (Issue 1759)
Differin Epiduo gel (Galderma), a fixed-dose combination of
the synthetic retinoid adapalene 0.1% and the oxidizing agent
benzoyl peroxide 2.5%, is now available over the counter (OTC)
for topical treatment of acne in patients ≥12 years old. It will remain available by prescription for
use in patients 9-11 years old. A gel containing adapalene
0.3% and benzoyl peroxide 2.5% (Epiduo Forte, and generics)
is available by prescription for use in patients ≥12 years old.
4
In Brief: New Warning for OTC Orlistat (Alli)
The Medical Letter on Drugs and Therapeutics • July 20, 2026; (Issue 1759)
The FDA now requires a warning about a risk of acute kidney
injury in the product label for the 60-mg capsules of the
pancreatic and gastric lipase inhibitor orlistat, which are
available over the counter as Alli for weight loss.1 The label
for the 120-mg capsules, which are available by prescription
as Xenical, already includes a warning about a risk of
oxalate nephrolithiasis and oxalate nephropathy (orlistat
increases oxalate absorption).
5
Treatment of Allergic Rhinitis and Allergic Conjunctivitis
The Medical Letter on Drugs and Therapeutics • March 31, 2025; (Issue 1725)
Initial treatment of allergic rhinitis (AR) depends
on the severity of symptoms and whether they are
intermittent or persistent (see Table 1).
6
Antiviral Drugs for Seasonal Influenza for 2025-2026
The Medical Letter on Drugs and Therapeutics • October 27, 2025; (Issue 1740)
Influenza is generally a self-limited illness, but complications
including pneumonia, respiratory failure, and
death can occur, especially in persons at increased
risk (see Table 1).
7
Sunscreens
The Medical Letter on Drugs and Therapeutics • June 23, 2025; (Issue 1731)
Excessive exposure to ultraviolet (UV) radiation can
cause erythema, photoaging, and skin cancer.
Sunscreens are widely used to reduce these risks, but
questions remain about their effectiveness and safety.
In 2021, the FDA proposed a rule that would require
additional safety studies for some sunscreen active
ingredients and mandate better UVA protection in
sunscreen products.
8
COVID-19 Update: 2025-2026 Vaccine Formulations and Recommendations
The Medical Letter on Drugs and Therapeutics • October 13, 2025; (Issue 1739)
The FDA has licensed new 2025-2026 formulations
of the mRNA COVID-19 vaccines manufactured by
Pfizer/BioNTech (Comirnaty) and Moderna (Spikevax,
mNEXSPIKE) and the adjuvanted protein subunit
COVID-19 vaccine manufactured by Novavax
(Nuvaxovid). The new formulations are indicated
for use in all adults ≥65 years old and in persons
6 months (Spikevax), 5 years (Comirnaty), or 12
years (mNEXSPIKE, Nuvaxovid) through 64 years old
who are at high risk for severe COVID-19 because
of an underlying condition. An Emergency Use
Authorization allowing administration of the Pfizer
vaccine to children 6 months through 4 years old has
been withdrawn.
9
Insect Repellents
The Medical Letter on Drugs and Therapeutics • July 12, 2021; (Issue 1628)
The Centers for Disease Control and Prevention
(CDC) and the Environmental Protection Agency
(EPA) recommend using insect repellents to prevent
infections transmitted by mosquitoes and ticks.
Insect repellents applied to exposed skin should be
used in conjunction with other preventive measures
such as wearing pants and long-sleeved shirts and
avoiding outdoor activities during peak mosquito-biting
times. Mosquitoes can transmit diseasecausing
pathogens, including Zika, chikungunya,
dengue, West Nile, eastern equine encephalitis, and
yellow fever viruses, and the malaria parasite. Ticks
can transmit the bacteria that cause Lyme disease,
the rickettsia that cause Rocky Mountain spotted
fever, and viruses such as Powassan virus. Some
insect repellents containing EPA-registered active
ingredients are listed in Table 1.
10
Drugs for Hypertriglyceridemia
The Medical Letter on Drugs and Therapeutics • July 20, 2026; (Issue 1759)
Adults with persistent fasting triglyceride levels ≥150 mg/dL
are considered to have hypertriglyceridemia; when levels are
≥500 mg/dL, it is considered severe. Hypertriglyceridemia
is associated with an increased risk of atherosclerotic
cardiovascular disease (ASCVD); severe hypertriglyceridemia
increases the risk of acute pancreatitis.
