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,...

The gram-positive anaerobic bacillus Clostridium difficile is the most common identifiable cause of antibiotic-associated diarrhea. The antibiotics most often implicated have been ampicillin, second and third generation cephalosporins, clindamycin and fluoroquinolones. The emergence in recent years of a new, more toxic epidemic strain (BI/NAP1), possibly related to widespread use of fluoroquinolones, has caused a marked increase in the incidence and severity of C. difficile-associated disease (CDAD).

The FDA has approved two new ophthalmic drugs for reduction of intraocular pressure (IOP) in patients with open-angle glaucoma or ocular hypertension: latanoprostene bunod (Vyzulta – Bausch and Lomb), a modified prostaglandin analog, and netarsudil (VRhopressa – Aerie), the first Rho kinase inhibitor to be approved in the US.

The FDA has approved daridorexant (Quviviq – Idorsia), an orexin receptor antagonist, for treatment of sleep-onset and/or sleep-maintenance insomnia in adults. Daridorexant is the third orexin receptor antagonist to be approved for this indication; suvorexant (Belsomra) and lemborexant (Dayvigo) were approved earlier.

In June 2021, the FDA approved the IV amyloid beta-directed monoclonal antibody aducanumab (Aduhelm) for treatment of Alzheimer’s disease. The approval did not restrict use of the drug to patients with mild cognitive impairment or mild dementia, which was the population enrolled in the clinical trials. Now, Biogen, with the permission of the FDA, has made an addition to the labeling of the drug that says: Treatment with Aduhelm should be initiated in patients with mild cognitive impairment or mild dementia stage of disease, the population in which treatment was initiated in clinical...

About 2.5 million persons in the US had hepatitis C between 2017 and 2020. Guidelines from the American Association for the Study of Liver Diseases (AASLD) and the Infectious Diseases Society of America (IDSA) on management of hepatitis C virus (HCV) infection were updated in 2023.

Four different desk-top systems are now widely used in physicians'; offices to measure blood chemistries. The Ektachem DT (Kodak) and Reflotron (Boehringer Mannheim), reviewed previously in The Medical Letter (volume 30, page 119, 1988; volume 31, page 90, 1989), resemble the Seralyzer (Miles Diagnostics) in cost; the Vision (Abbott), which is fully automated, is much more expensive.

Oxaprozin (Daypro -Searle), a propionic acid-derivative nonsteroidal anti-inflammatory drug (NSAID), has been approved by the US Food and Drug Administration for once-daily treatment of rheumatoid arthritis and osteoarthritis. Some of the NSAIDs previously marketed in the USA are listed in the table on page 16. Ibuprofen, naproxen, fenoprofen, ketoprofen, and flurbiprofen are also propionic acid derivatives. Piroxicam and nabumetone (Medical Letter, 34:38, 1992) are also approved for once-daily use, and indomethacin is available in an extended-release formulation that can be taken once...

Paclitaxel (Taxol - Bristol-Myers Squibb) is now available in the USA for treatment of metastatic ovarian cancer refractory to other drugs. The new drug is a natural product extracted in small amounts from the inner bark of the Western yew tree found mainly in the Pacific northwest (Taxus brevifolia). Efforts to synthesize the drug have been unsuccessful to date, but a semi-synthetic product (taxotere) prepared from the needles of European yews has shown some promise (R Pazdur et al, J Natl Cancer Inst, 89:1781, 1992), and a fungus (Taxomyces andreanae) growing on the Pacific yew was...

Terbinafine 1% cream (Lamisil - Sandoz), an allylamine synthetic antifungal drug chemically related to naftifine (Naftin - Medical Letter, 30:98, 1988), is now available in the USA for topical treatment of tinea pedis, tinea cruris, and tinea corporis infections. An oral formulation is available in Europe and is under investigation here.