NEW DRUG WARNINGS
Changes to labeling of enoxaparin (Lovenox) and bevacizumab (Avastin).
A warning has been added to the labeling of enoxaparin (Lovenox), a low-molecular-weight heparin, indicating that it increases the risk of bleeding in the presence of severe renal impairment or low body weight.
Because the enoxaparin dose should be decreased in patients with severe renal impairment (as indicated by a creatinine clearance of less than 30mL/min), the revised label includes a table in the dosage and administration section that has specific dosing recommendations applicable to such patients. Patients with mild (creatinine clearance of 50 to 80 mL/min) or moderate (creatinine clearance of 30 to 50 mL/min) renal impairment don't need to have dosage adjusted. "Low-weight women," defined by the manufacturer as those weighing less than 45 kg, and "low-weight men," defined by it as those weighing less than 57 kg, should be observed more closely for signs and symptoms of bleeding, but they don't need to take a decreased dose of enoxaparin.
Bevacizumab (Avastin) was approved in February 2004 by the U. S. Food and Drug Administration (FDA) for use in combination with intravenous 5-Fluorouracil (5-FU)-based chemotherapy to treat patients with previously untreated metastatic cancer of the colon or rectum. Bevacizumab inhibits angiogenesis, the process by which new blood vessels develop and carry vital nutrients to a tumor. A new warning concerning the drug has been issued because it has been found to increase the risk of serious arterial thromboembolic events, such as stroke, myocardial infarction, transient ischemic attacks, and angina.
In recent studies, the risk of a serious arterial thrombotic event was found to be about two times greater in patients receiving both 5-FU - based chemotherapy and bevacizumab than it was in those receiving only the former, and the overall rate of incidence of this adverse effect is believed to be 5%. A revised drug label is expected to be issued soon. Nurses should monitor patients receiving the drug for signs of arterial thromboembolic events. Any serious adverse effects related to drug therapy with bevacizumab can be reported to the FDA MedWatch system (by telephone, 1-800-FDA-1088, by fax, 1-800-FDA-0178, or online at http://www.accessdata.fda.gov/scripts/medwatch/).
U.S. Food and Drug Administration. Lovenox. 2004. http://www.fda.gov/medwatch/SAFETY/2004/safety04.htm#lovenox; U.S. Food and Drug Administration. Avastin. 2004. http://www.fda.gov/medwatch/SAFETY/2004/safety04.htm#avastin.
NEW DRUG APPROVALS
Treatments for alcoholism, radiation contamination, HIV infection, and superficial basal cell carcinoma.
Acamprosate (Campral), the first new drug approved for alcohol abuse in a decade, has been approved for the treatment of alcoholics who have stopped drinking and seek to remain abstinent.
Acamprosate is a synthetic, centrally acting drug that has a structure similar to that of the neurotransmitter gamma-aminobutyric acid (GABA). Although its exact mechanism of action is not well understood, it's believed to work on the specific pathways of the brain involved in alcohol abuse. Three placebo-controlled clinical studies involving nearly 1,000 patients demonstrated the drug's efficacy in maintaining abstinence from alcohol once detoxification had been achieved. Interestingly, in a fourth study, patients who had not given up drinking at the beginning of drug therapy and those who were also abusing substances other than alcohol, didn't receive any benefit of acamprosate. The drug has been approved during the past decade in more than 30 countries, across most of Europe, Australia, Hong Kong, South Africa, and much of Latin America. Administered in a "timed-release" enteric-coated tablet, it's not addicting and generally is tolerated well, the most common adverse effects being headache, diarrhea, flatulence, and nausea.
Two drugs, pentetate calcium trisodium injection (Ca-DTPA) and pentetate zinc trisodium injection (Zn-DTPA), are the first to be approved by the FDA for the treatment of internal contamination with the radioactive elements plutonium, americium, and curium, which can occur through various routes such as ingestion, inhalation, or direct contact with nonintact skin, such as an open wound. Already in use for several decades as investigational drugs used in the treatment of people contaminated with radioactive material, they work by increasing the rate of the elimination of such material from the body, and it's hoped that this decreases the long-term risk incurred from exposure to it. The drugs aren't administered simultaneously; if both are available, Ca-DTPA, a more effective medication in the first 24 hours after contamination, should be administered initially, and the regimen changed subsequently to Zn-DTPA if it's necessary to continue treatment, as the latter induces less loss of nutritional metals, such as zinc, for which oral supplementation would be necessary. Normally, both drugs are administered intravenously, but they may be administered via nebulization in cases of contamination by inhalation.
Two new drug combinations of nucleoside reverse transcriptase inhibitors (NRTIs) have been approved by the FDA for treating HIV-1 infection-Epzicom, a combination of abacavir and lamivudine, and Truvada, a combination of tenofovir and emtricitabine, both of which are manufactured in fixed doses and administered with other types of drugs used to treat HIV, such as the protease inhibitors and the nonnucleoside reverse transcriptase inhibitors, for fully effective therapy. While the combination therapy doesn't afford any unique therapeutic benefit, it does simplify the regimen, and a less complex dosing schedule helps to promote adherence to drug therapy, which is critical to the success of any HIV drug regimen because a consistent therapeutic level is necessary to avert HIV mutation, which can lead to drug resistance.
Imiquimod (Aldara) topical cream, already approved by the FDA for use in treating actinic keratosis and external genital warts, has now been approved by the agency also for use in the treatment of superficial basal cell carcinoma, a form of skin cancer. The drug is to be used to treat superficial basal cell carcinoma that is on the body, neck, arms, or legs, but not on the face, and only if surgery is not medically appropriate, as successful treatment of the disease is most effectively accomplished with surgical removal. The most frequent adverse effects of imiquimod therapy are localized reactions such as redness, swelling, a sore or blister, peeling, itching, and a burning sensation. Nurses should be sure to inform patients of the importance of follow-up visits after the course of therapy to confirm that the skin cancer has been completely treated.
U.S. Food and Drug Administration. FDA approves new drug for treatment of alcoholism. 2004. http://www.fda.gov/bbs/topics/ANSWERS/2004/ANS01302.html; U.S. Food and Drug Administration. Center for Drug Evaluation and Research. Overview: Campral. 2004. http://www.accessdata.fda.gov/scripts/cder/drugsatfda/index.cfm?fuseaction=Searc; U.S. Food and Drug Administration. FDA approves drugs to treat internal contamination from radioactive elements. 2004. http://www.fda.gov/bbs/topics/news/2004/NEW01103.html; U.S. Food and Drug Administration. Campral. 2004. http://www.fda.gov/cder/foi/label/2004/21431lbl.pdf; U.S. Food and Drug Administration. Statistical review and evaluation: acamprosate. 2004. http://www.fda.gov/ohrms/dockets/ac/02/Briefing/3857B1_04_FDA-statistical.htm; U.S. Food and Drug Administration. FDA approves two fixed-dose combination drug products for the treatment of HIV-1 infection. 2004. http://www.fda.gov/bbs/topics/news/2004/NEW01099.html; U.S. Food and Drug Administration. FDA approves new use of drug to treat superficial basal cell carcinoma, a type of skin cancer. 2004. http://www.fda.gov/bbs/topics/news/2004/NEW01088.html.