Many prescriptions for eye drops call for instillation of 1-2 drops. But Medical Letter consultants in ophthalmology seem to agree that all eye drops should generally be given in doses of only one drop. The volume of a single drop can vary with the viscosity of the solution, the design of the dropper, and patient technique. The average volume of a drop is 35-50 microliters, but can be as high as 75 microliters. An eye brimming with fluid holds 30 microliters at best, so even one drop is often an overdose. A second either washes out the first or increases the possibility of systemic toxicity,...

In overactive bladder, involuntary bladder contractions due to detrusor overactivity result in urinary urgency, frequency, nocturia, and incontinence. The prevalence of the disorder increases with age. Nonpharmacologic treatment, including bladder training, urge suppression, pelvic floor muscle exercises, constipation management, modification of fluid intake, and avoidance of dietary irritants such as alcohol and caffeine, should be tried first.

Pharmacologic management of opioid withdrawal symptoms can reduce the intensity of drug craving and improve treatment retention in patients with opioid use disorder who will receive maintenance treatment. Withdrawal management without subsequent maintenance treatment is associated with high rates of relapse, overdose death, and HIV and/or hepatitis C virus infection. Several guidelines on management of opioid withdrawal are available. Maintenance treatment of opioid use disorder was reviewed in a previous issue.

View the Comparison Table: Drugs for Parkinson's Disease

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.

Many different drugs are used for treatment of osteoarthritis pain, but none of them prevent progression of the disease. Nonpharmacologic approaches including weight management, exercise, tai chi, physical therapy, assistive devices, and total joint arthroplasty can also be used. The American College of Rheumatology (ACR) has published new guidelines for the management of osteoarthritis of the hip, hand, and knee.

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.

View the Comparison Table: Some Oral Antiseizure Medications

A new CDC guideline for prescribing opioids for pain recently became available. Nonopioid drugs for pain were reviewed in a previous issue.

Intrauterine devices (IUDs) and the etonogestrel implant are the most effective reversible contraceptive methods available. Hormonal oral contraceptives, patches, rings, and injectables are also effective in preventing pregnancy. When used alone, barrier and behavioral methods generally have higher failure rates than other methods (see Table 1). Selection of a contraceptive method is usually based on patient-specific factors and personal preference