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 injectable direct thrombin inhibitor desirudin (Iprivask – Canyon), a recombinant analog of hirudin, the leech anticoagulant protein, was approved by the FDA in 2003 for prevention of venous thromboembolism (VTE) after elective hip arthroplasty, but was only marketed recently in the US. It has been available in Europe as Revasc for about 10 years. Two other hirudin analogs are available in the US: lepirudin (Refludan) for treatment of heparin-induced thrombocytopenia (HIT) and bivalirudin (Angiomax) for use in percutaneous coronary intervention (PCI).

Infertility occurs in about 15% of couples. About one third of infertility is due to problems with ovulation or an anatomic abnormality of the fallopian tube or peritoneum, such as scarring, adhesions or endometriosis. Another third is due to a male infertility factor, most commonly insufficient sperm production or abnormal motility or morphology. The remaining third is unexplained. In older women unexplained infertility is probably caused by diminished quality and quantity of oocytes, decreased implantation and spontaneous pregnancy wastage.

Ziprasidone (Geodon - Pfizer), a benzisothiazolyl piperazine, has been approved by the FDA for oral treatment of schizophrenia. An intramuscular formulation will probably be available in the near future.

Azelastine hydrochloride, a histamine-H1 receptor antagonist, has been marketed as a 0.1% nasal spray (Astelin - Wallace) for treatment of seasonal allergic rhinitis. Corticosteroid and cromolyn sodium nasal sprays are also available for this indication (Medical Letter, 37:5, 1995). Cromolyn sodium (Nasalcrom) has now been approved for over-the-counter use.

Bosentan (Tracleer - Actelion), a non-peptide endothelin receptor antagonist, has been approved by the FDA for oral treatment of patients who have pulmonary arterial hypertension (PAH) with symptoms of dyspnea at rest or with minimal exertion.

Valdecoxib (Bextra - Pharmacia/Pfizer), a selective cyclooxygenase (COX-2) inhibitor similar to celecoxib (Celebrex) and rofecoxib (Vioxx), was recently approved by the FDA for treatment of osteoarthritis, rheumatoid arthritis and primary dysmenorrhea.

The FDA has approved the marketing of tolvaptan (Samsca - Otsuka), an oral vasopressin receptor antagonist, for treatment of hypervolemic or euvolemic hyponatremia due to congestive heart failure (CHF), cirrhosis or the syndrome of inappropriate antidiuretic hormone secretion (SIADH). A similar drug, conivaptan (Vaprisol) is already available for intravenous (IV) treatment of euvolemic hyponatremia in hospitalized patients. Tolvaptan was approved by the FDA for both inpatient and outpatient use, but it should be started in a hospital.

The FDA has approved dupilumab (Dupixent – Sanofi/Regeneron), a subcutaneously-injected fully human monoclonal antibody, for treatment of adults with moderate to severe atopic dermatitis (eczema) that has not responded to topical therapies. It can be used with or without topical corticosteroids.

The FDA has approved Cobenfy (BMS), an oral fixed-dose combination of the muscarinic agonist xanomeline and the peripheral muscarinic antagonist trospium chloride, for treatment of schizophrenia in adults. It is the first antipsychotic drug to be approved in the US for treatment of schizophrenia that does not block dopamine receptors. This is the first approval for xanomeline; trospium has been available for many years for treatment of overactive bladder.