Pharmacology Update
The Latest Information on New Drugs and NewIndications
By William T. Elliott, MD
The national institutes of health (nih) is considering a head-to-head trial between tamoxifen (Nolvadex, Zeneca) and raloxifene (Eli Lilly) for breast cancer prevention. The study would look at more than 22,000 women who are at increased risk for breast cancer over five years. Both drugs have been shown to reduce the risk of breast cancer in women, but it is postulated that raloxifene is associated with less side effects. The five-year study will be considered by the NIH in the next several months.
Protease inhibitors may have long-term effects on lipid metabolism and may result in unusual patterns of fat deposition. Fat accumulation in the abdominal wall and the back of the neck has been commonly observed in patients taking Crixivan and other protease inhibitors. A recent report from Minnesota (Lancet 1998;351:1328) suggests that the drugs may also contribute to premature coronary artery disease. Coronary disease was described in two young men aged 28 and 37, and the development of hyperlipidemia was noted in 41 out of 124 patients treated with the anti-retroviral drugs. With most treated patients living free of disease for years, focus on heart disease prevention may be warranted.
There is more bad news for calcium channel blockers (CCBs). Two recent reports suggest that the drugs may indeed be associated with increased risk of fatal and nonfatal myocardial infarction. The Appropriate Blood Pressure Control in Diabetes trial (N Engl J Med 1998;338:645-652), in which the CCB nisoldipine was compared to enalapril in 470 patients, was stopped prematurely when it was observed that even though there was similar BP control in the two groups, there was an excess in fatal (5 vs 10) and nonfatal MIs (5 vs 22) in the nisoldipine group. In a separate report, results from the Nurses Health Study were recently published (Circulation 1998;97:1540-1548). The outcomes of hypertension treatment with a variety of BP classes was reviewed in more than 14,000 women. CCBs were associated with a 64% increase in myocardial infarction when compared to diuretics. For women with no history of cardiovascular disease at the outset of the study, there was a 65% increase in MI.
Just as Viagra mania is peaking, two new alprostadil preparations are being developed. PowderJect Pharmaceuticals, makers of needle-free parenteral delivery systems, has announced promising results with alprostadil. Delivered as a dry powder at high speed directly into the skin of the penis via a gas-powered injector, the system was effective in healthly volunteers. Another company, NexMed, has tested a topical alprostadil cream that is rubbed into the penis. In a company sponsored study from Argentina, it was reported that the cream was as effective as intracavernous injections. Obviously already in development when Viagra was introduced, the companies still feel there is a market for alprostadil for the treatment of erectile dysfunction for men in whom Viagra is ineffective.
The American College of Obstetricians and Gynecologists 46th Annual Clinical Meeting in early May was the site of one of the more interesting debates over the use of hormone replacement therapy (HRT). Susan Love, MD, of UCLA and Charles Hammond, MD, of Duke University discussed the pros and cons of HRT, with the discussion occasionally becoming heated. Love, a surgeon who has written a book on HRT and breast cancer, is an outspoken critic of obstetricians and gynecologists who prescribe hormones to postmenopausal women. Hammond feels that the benefit of HRT on osteoporosis and disease outweighs the risk of breast cancer and that the risk of breast cancer is overstated.
Intravenous immune globulin (IVIG) is in increasingly short supply, as pharmacists scramble nationwide to secure supplies for their patients. The shortage is the result of a number of factors occurring at once. Increased off-label use for diseases, such as chronic fatigue syndrome or multiple sclerosis, coupled with production problems are the main causes for the shortage. The FDA also recalled some batches of IVIG last year because of concern over the spread of Creutzfeldt-Jakob disease. The shortage has become so severe that, in some areas, the drug is being rationed to preserve supplies for those who require it for life-threatening conditions. Currently, the only FDA-approved indications for IVIG are primary immunodeficiency, idiopathic thrombocytopenic purpura, Kawasaki syndrome, bone marrow transplantation, chronic B-cell lymphocytic leukemia, and pediatric HIV infection.
Waiting an hour for Viagra to work may not be satisfactory for some patients, so Pfizer is working with R.P. Schere corporation to develop a rapid delivery system-a Viagra wafer that would dissolve in the mouth and allow patients to take the drug minutes prior to intercourse rather than an hour or two prior. In other Viagra news, health plans are still debating whether the drug is a medical necessity or a luxury item (similar to cosmetic drugs such as Retin-A or Rogaine). Many health plans are electing to cover the drug with strict guidelines; however, one main stumbling block to establishing coverage guidelines is determining how much Viagra constitutes a month's supply. Some health plans are using the average rate of intercourse for American couples, two times per week, as the starting point for determining the number of pills to be covered per month. Finally, the popularity of Viagra has spun off opportunities for drug manufacturers in other areas. Bradley pharmaceuticals has announced a new vaginal lubricant liquid that can be used by either men or women. It is anticipated that the renewed interest in sexual activity in the aging population will create a vigorous market for lubricants.
You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
- Award-winning Medical Content
- Latest Advances & Development in Medicine
- Unbiased Content