1. Aschenbrenner, Diane S. MS, APRN, BC

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The drug pregabalin (Lyrica) has received Food and Drug Administration (FDA) approval as the first medication for the treatment of fibromyalgia. The drug had already been approved for the treatment of the pain of diabetic peripheral neuropathy and postherpetic neuralgia and as adjunctive therapy for partial seizures in adults. Pregabalin is believed to alleviate pain and inhibit seizures by binding to the [alpha]2[delta] site (an auxiliary subunit of voltage-gated calcium channels) in central nervous system tissues. When the drug is attached at the site, the release of calcium is diminished, which in turn diminishes the release of the calcium-dependent neurotransmitters that induce neuropathic pain and seizures.


The two clinical trials of pregabalin, in which approximately 1,800 subjects were enrolled, were short-term studies, one lasting 14 weeks and the other six months. According to a visual analogue scale, as many as 54% of patients reported at least a 50% improvement in level of pain, but not all responded to the therapy. The most common adverse effects of the drug (dizziness, somnolence, dry mouth, edema, blurred vision, weight gain, difficulty concentrating) and the warnings pertaining to it remain as already noted.


The FDA has also approved a new drug for the treatment of advanced renal cell carcinoma. Temsirolimus (Torisel) is an inhibitor of kinase that binds to an intracellular protein (FKBP-12), inhibiting mTor (mammalian target of rapamycin) and thereby preventing cell division and causing the cessation of tumor cell growth. The drug's principal active metabolite, sirolimus (Rapamycin, Rapamune), is used as an immunosuppressant after kidney transplantation to prevent organ rejection. Patients in clinical trials who received temsirolimus lived statistically significantly longer than did those who received interferon alfa, the standard therapeutic agent used to treat advanced renal cell carcinoma, although the survival time was still shorter than one year (a median of 10.9 and 7.3 months, respectively). Survival free of disease progression also was significantly longer but still remained fairly short, a median of five and a half months with temsirolimus and just over three months with interferon alfa.


Temsirolimus is administered by iv infusion for 30 to 60 minutes once weekly for as long as it is effective. Because hypersensitivity reactions to the drug are possible, an H1-antihistamine should be administered 30 minutes before infusion. Patients with known hypersensitivity to temsirolimus, any of its metabolites, including sirolimus, or an antihistamine, should be closely observed. Because the directions for diluting and administering temsirolimus are quite specific, nurses should, of course, read them carefully before administration. Most patients who have received temsirolimus developed elevated levels of serum glucose and serum lipids, both of which should be monitored closely during therapy. Use of the drug has been associated also with fatal bowel perforation and sometimes fatal acute renal failure not related to progression of disease, possible complications for which patients should be monitored. Because temsirolimus is immunosuppressive, patients should be monitored also for symptoms of infection.


FDA approves first drug for treating fibromyalgia. FDA News 2007 Jun 21.;


FDA approves new drug for advanced kidney cancer. FDA News 2007 May 30.;


Prescribing information: Lyrica (pregabalin) capsules. 2007.;


Prescribing information: Torisel (temsirolimus) injection. 2007.