The motor symptoms of Parkinson's disease (PD) are caused primarily by degeneration of dopaminergic neurons in the substantia nigra. The nonmotor symptoms of the disease are thought to be caused by degeneration of other neurotransmitter systems. No disease-modifying drugs are available for treatment of PD.

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.

View the Comparison Table: Inhaled Drugs for Treatment of COPD

Among patients with chronic heart failure, those with a left ventricular ejection fraction (LVEF) ≤40% are considered to have heart failure with reduced ejection fraction (HFrEF). Patients with a LVEF ≥50% are considered to have heart failure with preserved ejection fraction (HFpEF). Those with a LVEF of 41-49% are an intermediate group more similar to patients with HFpEF.

Cholesterol management guidelines from the American College of Cardiology/American Heart Association Task Force were last published in 2019.

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

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....

Primary hypothyroidism is usually the result of Hashimoto's (autoimmune) thyroiditis, thyroidectomy, or radioactive iodine therapy. Treatment of hypothyroidism with replacement doses of thyroid hormone is usually lifelong. Levothyroxine (LT4; synthetic thyroxine; Synthroid, and others) is the drug of choice.1

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.

About 60% of men ≥60 years old have clinically relevant prostatic enlargement due to benign prostatic hyperplasia (BPH). The goals of treatment are to decrease lower urinary tract symptoms and to prevent disease progression and complications such as acute urinary retention. The American Urologic Association's guidelines for treatment of BPH were recently updated.