Influenza is generally a self-limited illness, but pneumonia, respiratory failure, and death can occur, especially in persons at increased risk for influenza complications (see Table 1). Updated information on influenza activity and antiviral resistance is available from the CDC at cdc.gov/flu.

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.

Most patients with multiple sclerosis (MS) present with the relapsing-remitting form of the disease. Pharmacologic treatment usually includes a disease-modifying drug, corticosteroids for acute exacerbations, and other drugs for managing symptoms such as fatigue, depression, and pain. Early use of disease-modifying therapy has improved clinical outcomes.

Gastroesophageal reflux disease (GERD) is the most common GI condition encountered in the outpatient setting; it affects about 20% of people in the US.

Atrial fibrillation (AF) is the most common arrhythmia in the world. Risk factor modification, anticoagulation, rhythm control, and rate control are the four pillars of its management. American College of Cardiology/American Heart Association (ACC/AHA) guidelines on management of AF were updated recently.

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).

Psoriatic arthritis is a chronic inflammatory arthropathy associated with psoriasis. A recent review found that about 20% of patients with psoriasis have psoriatic arthritis. Updated guidelines for treatment of psoriatic arthritis have recently been published.

Diet, exercise, and weight loss can improve glycemic control, but almost all patients with type 2 diabetes require antihyperglycemic drug therapy. Treating to a target A1C of <7% while minimizing hypoglycemia is recommended to prevent microvascular complications of diabetes (retinopathy, nephropathy, and neuropathy). An A1C target of <8% may be appropriate for some older patients.

Primary hypothyroidism is usually the result of Hashimoto's thyroiditis, thyroidectomy for hyperthyroidism, goiter or cancer, or radioactive iodine therapy for hyperthyroidism.

The drugs of choice for treatment of viral infections (other than HIV) and their dosages are listed in Tables 1-6 on the pages that follow. Some of the indications and dosages recommended here have not been approved by the FDA. Vaccines used for the prevention of viral infections are discussed elsewhere.