New & Approved: Relenza * Plan B tablets.
(zanamivir for inhalation, Glaxo Wellcome)
An antiviral for treating uncomplicated influenza in people aged 12 and older, who have had symptoms for no more than 2 days. The first neuraminidase inhibitor to be approved.
* Recommended Dosage: 10 mg inhaled twice a day for 5 days, administered in a dry powder formulation with a hand-held, breath-activated device.
* Special Considerations: Tolerated significantly better than amantadine and rimantadine, previously the only available antivirals for treating flu, which have unpleasant side effects that have limited their use. In studies, bronchospasm and reductions in [FEV.sub.1] have been reported in some people with asthma and chronic obstructive pulmonary disease. Those with underlying respiratory disease should have a fast-acting inhaled bronchodilator nearby during treatment.
* Comment: Neuraminidase inhibitors block the influenza enzyme that promotes viral release from infected cells and are effective against both influenza A and B.
In two international studies of people aged 12-64 with the flu, treatment reduced symptoms by a mean of 1.5-2.5 days over placebo, a significant difference, vs. only 1 day in the pivotal North American trial of more than 500 people-part of the reason most of an expert panel recommended against approval at a hearing earlier this year.
Despite the statistically insignificant results of the North American trial, every study of Relenza conducted to date "has consistently shown a benefit on the order of 1-2 days" over placebo, said Dr. JohnJ. Treanor, an investigator in studies of Relenza and an oral neuraminidase inhibitor manufactured by Roche, which may also be approved in time for this flu season.
There is no direct evidence that neuraminidase inhibitor treatment reduces serious sequelae of the flu, but "encouraging" preliminary evidence suggests that treatment with Relenza or the Roche product reduces the rates of secondary complications, added Dr. Treanor of the University of Rochester (N.Y.).
He has received research funding and honoraria from Glaxo Wellcome and Roche and has served on the speakers bureaus for both companies.
Plan B tablets
(levonorgestrel, Women's Capital Corporation)
A progestin-only method of preventing pregnancy after unprotected intercourse or contraceptive failure. The second product developed and approved specifically as an emergency contraceptive.
* Recommended Dosage: First tablet taken within 72 hours of intercourse (most effective when taken within 12 hours); second dose taken 12 hours later. Bach tablet contains 0.75 mg of levonorgestrel, equal to about 20 Ovrette pills, so is more convenient to take.
* Special Considerations: Progestin-only emergency contraceptive pills (ECPs) are associated with about half the nausea and vomiting of the so-called Yuzpe method, a combination of levonorgestrel and ethinyl estradiol pills. An over-the-counter antiemetic 1 hour before the first dose can still be recommended.
* Comment: Studies have found that the levonorgestrel-only method reduces the pregnancy rate after unprotected intercourse by nearly 90%, compared with about 75% with the Yuzpe method. The former is possibly more effective because it causes less nausea, and women are more likely to take the second dose, said Dr. Anita Nelson, professor of ob.gyn. at the University of California, Los Angeles.
Ongoing research should pinpoint the exact mechanism of ECPs, but the available data indicate that they are likely to work by inhibiting ovulation when taken early enough and may also inhibit fertilization or prevent implantation, she added.
The most important role physicians can play in prescribing ECPs is to provide advance prescriptions to every woman who "needs a little safety net," such as those relying on condoms, diaphragms, or natural family planning, who can keep the ECPs handy in their medicine cabinets, emphasized Dr. Nelson, who has no financial ties to Plan B's manufacturer.
Until later this year, Plan B will only be available through Planned Parenthood clinics and other ECP providers listed on the Emergency Contraception Web site and 24-hour hot line (www.princeton.edu and 888-NOT-2-LATE).
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|Publication:||Family Practice News|
|Article Type:||Brief Article|
|Date:||Sep 15, 1999|
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