Am Fam Physician. 1999;59(4):1054-1062
Guidelines for Use of Sildenafil
The American Heart Association (AHA) and the American College of Cardiology (ACC) have issued an expert consensus document with recommendations for the safe and appropriate use of sildenafil (Viagra) when treating sexual dysfunction in patients at clinical risk of cardiovascular effects. Published in the January 1999 issue of the Journal of the American College of Cardiology and the January 5, 1999, issue of Circulation: Journal of the American Heart Association, the 10-page document covers the following topics: erectile dysfunction; pharmacokinetics, metabolism, mechanism of action and pharmacodynamics of sildenafil; drug–drug interactions and concomitant disease states; and cardiovascular effects of sexual intercourse in patients with coronary artery disease.
“We formulated these recommendations to appropriately caution, and not to unduly alarm, physicians who may wish to prescribe the drug to their patients with cardiovascular disease,” explained Melvin D. Cheitlin, M.D., emeritus professor of medicine at the University of California, San Francisco. Dr. Cheitlin cochaired the document's writing group with Adolph M. Hutter, Jr., M.D., a cardiologist at Massachusetts General Hospital.
The primary recommendation of the consensus panel is that sildenafil should not be used by patients taking organic nitrates. Concomitant use of the two drugs can result in dangerously low blood pressure. An appendix in the report contains a list of representative organic nitrates.
The consensus document also advises physicians to perform an individual clinical assessment before prescribing sildenafil to the following types of patients:
Those with angina or a positive exercise stress test.
Those with congestive heart failure with borderline low blood volume and low blood pressure.
Those who are taking multiple medications to control high blood pressure.
Those taking other medications or have conditions that can prolong the duration of action of the drug.
Scientific Exhibit Deadline for AAFP Assembly
A call for scientific exhibits has been issued by the American Academy of Family Physicians (AAFP) for possible presentation at the 1999 Scientific Assembly to be held September 15–19 in Orlando. The scientific exhibits open on September 16th. Applications must be submitted by April 1, 1999. Membership in the AAFP is not a prerequisite for submission. Scientific exhibits provide a forum for the presentation of research that is of interest and educational value to family physicians. The exhibits include those presented by residents and medical students.
Travel grants of $1,000 may be awarded to a maximum of 15 resident/student scientific exhibitors whose applications are accepted for presentation at the assembly. In addition, cash awards for first, second, third and fourth places may be presented to resident/student exhibitors. Application forms may be obtained from Vicky Binder, Scientific Assembly Department, AAFP, 8880 Ward Pkwy., Kansas City, MO 64114; telephone: 800-274-2237, ext. 5264.
At-Home Laser Treatment for Persons with Diabetes
A laser device (the Cell Robotics' Lasette) that offers persons with diabetes a way to draw their blood without using traditional lancets has been approved by the U.S. Food and Drug Administration. The portable device, a battery-operated Erbium:YAG laser, uses laser energy to penetrate the skin.
In clinical trials, patients who were adequately trained to use the device performed finger sticks with the laser device as easily and accurately as with lancets. Effective use of the lasette has been demonstrated in both adults and juveniles.
Use of the lasette requires instructions and proper maintenance to be safe and effective. Patients need to receive training and instructional material from the physician who prescribes the device.
Decrease in Incidence of Hib Disease
Widespread vaccination against Haemophilus influenzae type b (Hib) disease has nearly eliminated the incidence of this disease which, until recently, was the most common cause of bacterial meningitis among preschool-age children, according to a report in the November 27, 1998, issue of Morbidity and Mortality Weekly Report.
Despite this dramatic decline, Hib disease continues to circulate and U.S. children who do not receive their primary vaccination series on time or who are too young to be vaccinated are at risk of invasive Hib disease that can cause bacterial meningitis.
From 1989 to 1997, the report notes that the race-adjusted incidence of invasive Hib disease among children under five years of age declined by 99 percent. During 1996–1997, 79 cases of invasive H. influenzae disease were reported among children under five years of age. Of these cases, 14 (18 percent) were caused by infection with type b H. influenzae; 48 (61 percent) were caused by infection with non–type b H. influenzae; and 17 (22 percent) were caused by infection with unknown serotypes. The median incidence was higher among blacks than among all other groups.
Up to 60 percent of invasive Hib disease occurs in children before they reach 12 months of age. Children who receive the Hib vaccine are much less likely to carry the bacteria, decreasing the chance that younger, unvaccinated children will be exposed. After five years of age, few children contract invasive Hib disease.
Age-appropriate vaccination starting at two months continues to be the most important approach to protect children from invasive Hib disease. The report states that physicians should emphasize to parents the importance of vaccinating children against invasive Hib disease.
New Drug for Acute Organ Rejection
The U. S. Food and Drug Administration has approved the marketing of anti-thymocyte globulin, rabbit (Thymoglobulin), a new drug to help prevent organ loss for kidney transplant recipients experiencing acute rejection. The approval was based on results of a trial that included 163 patients and was conducted at 28 leading transplant centers in the United States.
The recommended dosage of Thymoglobulin is 1.5 mg per kg administered daily for seven to 14 days. Common adverse reactions, which are often transient, include fever, infections and thrombocytopenia. Use of Thymoglobulin is contraindicated in patients with known allergy to rabbit proteins, patients with an acute viral illness or patients with a history of anaphylaxis during rabbit immunoglobulin administration. For full prescribing information, call 650-688-2331.
Control of Asthma in Pregnant Women
The American College of Allergy, Asthma and Immunology (ACAAI) has launched a campaign to raise awareness among women with asthma and their physicians about the importance of controlling asthma during pregnancy. According to the ACAAI, asthma affects about 7 percent of pregnant women. The disease can cause complications for both mother and infant if not properly controlled during pregnancy.
To help control asthma symptoms and attacks, the ACAAI recommends that physicians work with their patients to develop a treatment plan that includes environmental control to limit exposure to asthma and allergy triggers and, if appropriate, the use of medication. Physicians should counsel their patients about the use of asthma and allergy medications during pregnancy. Women also need to know how their asthma symptoms might change when they become pregnant.
As part of the campaign, the ACAAI has created a consumer brochure titled “Advice from Your Allergist: Managing Asthma and Allergies During Pregnancy.” Copies of the brochure can be obtained by calling 800-842-7777. Information is also available on the ACAAI Web site at http://www.acaai.org/.
Warning for Immune Globulin Products
The U.S. Food and Drug Administration (FDA) has issued a letter to inform physicians to take safety precautions to reduce the potential risk of acute renal failure associated with the use of IGIV products (immune globulin intravenous [human]). Over 114 cases of renal dysfunction or acute renal failure have been reported since 1981.
Based on currently available data, the FDA recommends that the following precautions be taken when using IGIV products:
Make sure that patients are adequately hydrated before IGIV therapy is started.
Exercise particular caution in the use of IGIV products in patients at increased risk for acute renal failure, such as those with any degree of pre-existing renal insufficiency, diabetes, age over 65 years, volume depletion, sepsis, paraproteinemia and concurrent use of nephrotoxic drugs.
For patients at increased risk, physicians should weigh the potential benefits of administering sucrose-containing IGIV products against the risks of causing renal damage.
Do not exceed the recommended dose. Reduction in dose, concentration or rate of administration in patients at risk of acute renal failure has been proposed to reduce the risk of acute renal failure. Because of a lack of data, the FDA recommends that, for at-risk patients, physicians reconstitute/dilute the product in such a manner as to produce both the minimum concentration and the lowest rate of infusion practicable. For sucrose-containing IGIVs, a maximum infusion rate of 3 mg of sucrose per kg per minute should not be exceeded (Sandoglobulin, Panglobulin and Gammar-P IV have different recommendations).
Renal function, including urine output and blood urea nitrogen/serum creatinine, should be assessed before infusion of IGIV, particularly in patients who may be at increased risk for acute renal failure, and again at appropriate intervals. If renal function deteriorates, discontinuation of the product should be considered.
Newly revised package inserts are being prepared by the manufacturers of all IGIV products. Adverse events should be reported to the manufacturer or to the FDA's MedWatch program by telephone (800-FDA-1088), fax (800-FDA-0178) or mail (MedWatch, HF-2, 5600 Fishers Lane, Rockville, MD 20852-9787).
Call for Papers of Family Practice Research Presentations
The American Academy of Family Physicians (AAFP) is inviting researchers to submit papers for possible presentation at the 1999 Scientific Assembly to be held September 15–19 in Orlando. Applications must be submitted by April 1, 1999. Membership in the AAFP is not a prerequisite for submission.
Applications may be submitted in two different categories. Category I is for original research relevant to family practice; category II includes case studies and literature reviews. Each category has six author classifications: family physicians and fellows primarily in academic medicine, family physicians primarily in clinical practice, family practice residents, medical students, international attendees and others. The international attendee classification is open to anyone outside the United States who conducted clinical or educational research relevant to family medicine.
The best presentations in each category will receive cash awards of $1,000. Runners-up will receive $250. All awards are given at the discretion of the Subcommittee on Family Practice Research Presentations. Application forms may be obtained from Carrie Vickers, Scientific Assembly Department, AAFP, 8880 Ward Pkwy., Kansas City, MO 64114; telephone: 800-274-2237, ext. 5268.
AHCPR Report on Diagnosis of Sleep Apnea
Overnight full-channel polysomnography (full PSG) remains the “gold standard” for the diagnosis of sleep apnea, according to a study sponsored by the Agency for Health Care Policy and Research (AHCPR) under its evidence-based practice program. Because the full PSG is very expensive and is difficult to interpret, the primary objective of the AHCPR study was to evaluate the diagnostic accuracy of alternatives to full PSG for the diagnosis of sleep apnea. The sleep apnea evidence report is the first in a new series of evidence reports and technology assessments sponsored by the AHCPR.
Diagnostic approaches that might be alternatives to full PSGs or used as screening tests to better select patients for PSG testing include partial-channel PSGs, partial night or daytime PSGs, portable sleep monitoring devices for use at home, radiologic imaging of the head and neck, magnetic resonance imaging and computed tomography scans, anthropomorphic measurements, nasopharyngeal and laryngeal endoscopic measurements of both structure and function, and focused questionnaires. The study concluded that several of these less expensive and less time-consuming tests appear promising for the accurate diagnosis of sleep apnea.
Specific recommendations were not included in the report, but researchers believe that this synthesis of the evidence-based literature will serve as an information resource for physicians and developers of guidelines.
A summary of the report titled “Systematic Review of the Literature Regarding the Diagnosis of Sleep Apnea” is available on the AHCPR Web site at http://www.ahcpr.gov. The full report may be obtained free from the AHCPR Publications Clearing-house by calling 800-358-9295.
Modafinil for the Treatment of Narcolepsy
Modafinil (Provigil), a nonamphetamine drug, has been approved by the U.S. Food and Drug Administration to help improve wakefulness in patients with excessive daytime sleepiness associated with narcolepsy. Modafinil is the first new nonamphetamine drug in 40 years approved for the treatment of narcolepsy.
In two nine-week, multicenter placebo-controlled trials of more than 550 patients with narcolepsy, the subjects who received modafinil had a statistically significant increase in their ability to remain awake and had a statistically significant improvement in disease symptom severity, compared with those who received placebo.
Most adverse effects were mild to moderate and included headache, infection, nausea, nervousness, anxiety and insomnia. The manufacturer recommends that modafinil not be used in persons with a history of left ventricular hypertrophy or ischemic electrocardiographic changes, chest pain, arrhythmia or other clinically significant manifestations of mitral valve prolapse in association with central nervous system stimulant use.
Although modafinil has not been shown to produce functional impairment in clinical trials, the manufacturer notes that any drug affecting the central nervous system may alter judgment, cognitive or motor skills. Patients should be cautioned about operating an automobile or other hazardous machinery until they know that modafinil will not affect such activities. Full prescribing information can be obtained by calling 800-896-5855.