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.

Many readers have asked the Medical Letter to evaluate St. John's wort, an herbal extract now widely sold in health food stores and pharmacies, for its effectiveness and safety in the treatment of depression. St. John's wort is licensed in Germany for treatment of anxiety, depression and insomnia. In the USA, it is considered a dietary supplement and has not been evaluated by the FDA.

A biodegradable polymer 'wafer' (Gliadel - Rh ne-Poulenc Rorer) impregnated with the alkylating agent carmustine (BCNU; Bicnu) has been marketed in the USA for local treatment of recurrent glioblastoma multiforme that requires re-operation. The dime-sized polyanhydride wafers are implanted into the surgical cavity left behind after resection. Release of the alkylating agent directly into the area of the tumor bypasses the blood-brain barrier (H Brem and R Langer, Sci Med, 3:1, 1996).

Brinzolamide (Azopt - Alcon), a thieno-thiazine-6-sulfonamide carbonic anhydrase inhibitor, has been approved by the FDA in a 1% ophthalmic suspension for treatment of elevated intraocular pressure due to ocular hypertension or open-angle glaucoma. Brinzolamide is the second FDA-approved topical carbonic anhydrase inhibitor. Dorzolamide (Trusopt) was approved earlier (Medical Letter, 37:76, 1995).

Increased resistance of pneumococci to antimicrobial drugs may encourage more extensive use of pneumococcal polysaccharide vaccine.

The US Public Health Service Advisory Committee on Immunization Practices has recently published new recommendations for prevention and control of meningococcal disease in college students.

The February 14th issue of The Medical Letter reviewed natalizumab (Tysabri - Biogen Idec), a new monoclonal antibody that was granted accelerated approval because it decreased the number of relapses in patients with multiple sclerosis. On February 28th, the FDA issued a Public Health Advisory announcing that marketing of the drug had been suspended because 2 patients who had been treated with natalizumab for more than 2 years had developed progressive multifocal leukoencephalopathy, a rare, often fatal disease...

The FDA issued a public health advisory on March 10, 2005 warning about a risk of cancer with topical formulations of tacrolimus (Protopic) and pimecrolimus (Elidel) used to treat eczema in adults and children more than 2 years old. Elidel has been heavily promoted to the general public on television. The warning was based on reports of dose-related cancer in animals and 29 reports of cancer (including 8 skin malignancies and 12 lymphomas) in adults and children treated with these immunosuppressive drugs. Cause and effect have not been established. When Protopic was first marketed, The Medical...

The FDA has approved marketing of Zegerid powder for oral suspension (Santarus), an immediate-release formulation of the proton-pump inhibitor (PPI) omeprazole (Prilosec, and others). All other oral PPIs are delayed-release, enteric-coated formulations designed to prevent degradation of the drug by gastric acid. Each 20- or 40-mg packet of Zegerid contains 1680 mg of sodium bicarbonate, which protects the drug from gastric acid degradation. A dose of Zegerid contains 460 mg of sodium, which may be excessive for some patients. Zegerid is the first oral PPI to be approved by the FDA for...

No vaccines against tickborne encephalitis (TBE) or dengue are available in the US, but vaccines have been licensed in some other countries.