PAGE 18
HIV NUTRITION UPDATE
VOLUME 8, ISSUE 6
 
MED WATCH:   Lexiva (fosamprenavir calcium)

(Continued from page 17)
 
By William Palumbo, MS, RD, CDN
 

In these clinical trials Lexiva demonstrated: 
  • Durable anti-viral response through 48 weeks of therapy in ART-naive patients (<400 copies/mL 66 percent to 69 percent)
  • All grade 2-4 drug-related adverse events < 10 percent in ART-naïve patients 
  • Significantly less grade 2-4 drug-related diarrhea than Nelfinavir 
  • All grade 2-4 drug-related adverse events < 13 percent in PI-experienced patients
  • Flexible once or twice daily options in ART-naïve patients with no food or fluid restrictions 
  • No ART-naive patients receiving Lexiva/r developed any PI mutations. In PI-experienced patients, the following amprenavir resistance associated mutations were selected either alone or in combination: V32I, M46I/L, I47V, I50V, I54L/M and I84V. The clinical significance of resistance data is currently under evaluation.

 
 
 
 
 


 

Precautions: Lexiva interferes with one of the body's main mechanisms for eliminating drugs from the body. Serious or life-threatening drug interactions may occur if Lexiva is taken with some other drugs. Patients taking Lexiva must check with their doctor before taking any other medications. The drug should be taken twice daily in patients who have previously used other PI drugs to fight HIV. 

Coadministration of amprenavir and methadone can decrease plasma levels of methadone.  Agenerase may be less effective due to decreased amprenavir plasma concentrations in patients taking these agents together. Alternative antiretroviral therapy should be considered. Dosage of methadone may need to be increased when coadministered with Agenerase.

Women taking Lexiva/Agenerase should be instructed not to use hormonal contraceptives because some birth control pills (those containing ethinyl estradiol/norethindrone) decrease the concentration of amprenavir.  This may lead to loss of virologic response and possible resistance to Agenerase. Alternative methods of non-hormonal contraception are recommended.

As with Agenerase, Lexiva contains Vitamin E to improve it's bioavailability. Patients taking Lexiva should calculate their total intake of vitamin E, particularly if they take other dietary supplements with the antioxidant. Product information notes that each capsule contains 109 IU of vitamin E. Also, although patients may not absorb all of the vitamin E, this dose can exacerbate a vitamin K deficiency or bleeding from Coumadin. The implications of this blood thinning dose could be life threatening to those already on blood thinners. 
 

 
Side Effects: Lexiva's side effects include diarrhea, nausea, vomiting, headache, and rash. These side effects, however, were mild in most patients. Clinical trials showed moderate or severe side effects in fewer than 10% of people who had never received HIV treatment and in fewer than 13% of people previously treated with another PI. Elevations in cholesterol, triglyceride and liver transaminase blood levels may occur when Lexiva is co-administered with ritonavir.

References
 

  • Lexiva (fosamprenavir calcium) Prescribing Information. FDA Web Site.


 
 

 
 
Copyright 2004 HIV ReSources, Inc. Sharing this newsletter in any form with non-subscribers is strictly prohibited. Library/Institution subscribers are permitted to share HIV Nutrition Update html newsletter pages with up to five (5) employees or volunteers. NO other redistribution allowed. 
 
Please Help To Keep This Page Updated By Notifying
The Webmaster If You Find A Link That's Outdated!
 
HIV ReSources, Inc.
PO Box 39385
Fort Lauderdale, FL
33339-9385
USA
 
© 2004  HIV ReSources, Inc.
Any use of the information presented herein is done strictly at your own risk.
No responsibility is implied or intended on the part of HIV ReSources Inc,
the editor, or the publisher. Information on this site should not
be construed as an endorsement of any kind.
 
6/1/2004