Clostridioides (formerly Clostridium) difficile infection (CDI) is the most common infectious cause of healthcare-associated diarrhea in adults. Guidelines on management of CDI have recently been updated.

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.

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.

Annual vaccination against influenza A and B viruses is recommended in the US for everyone ≥6 months old without a contraindication. Influenza vaccines available in the US for the 2025-2026 season are listed in Table 2.

Drugs for gout are used to reduce the pain and inflammation of acute flares, decrease the frequency of exacerbations, and lower serum urate levels to prevent recurrent flares, development of tophi, and joint damage.

Opioid use disorder is a chronic, relapsing disease with physical and psychiatric components. It is associated with economic hardship, social isolation, incarceration, increased rates of blood-borne infections such as HIV and viral hepatitis, adverse pregnancy outcomes, and increased mortality. According to the NIH, there were 80,411 deaths involving an opioid in the US in 2021, more than in any previous year. Several guidelines on the management of opioid use disorder are available; all recommend maintenance pharmacotherapy as the standard of care.

Nonopioid drugs can be used in the treatment of many nociceptive and neuropathic pain conditions. For severe pain, especially severe chronic cancer pain, use of opioids may be necessary. Noninvasive nonpharmacologic treatments, including physical and psychological therapies, have been shown to improve pain and function in patients with some common chronic pain conditions and are unlikely to cause serious harms. A multimodal approach to analgesic therapy can increase pain control while reducing opioid use and adverse effects.

The goal of asthma treatment is to control symptoms, prevent exacerbations, and maintain normal lung function. Management of acute exacerbations in the emergency department is not discussed here.