A case series using famciclovir in stem cell transplant recipients with valacyclovir hypersensitivity reactions.
BACKGROUND
Herpes simplex virus and varicella zoster virus reactivation can occur in up to 32% and 40% of patients, respectively in the first year post-transplant without prophylaxis. Antiviral therapy consisting of acyclovir or valacyclovir is recommended for at least 1 year post stem cell transplant per evidence-based guidelines.


OBJECTIVE
In the event of a contraindication or hypersensitivity reaction to either drug, an alternative is essential based on the proven efficacy in reducing clinically significant herpes simplex virus and varicella zoster virus reactivations. We report two cases of successful initiation of famciclovir in stem cell transplant recipients experiencing hypersensitivity to valacyclovir or acyclovir.


CONCLUSIONS
In both cases, there were no hypersensitivity reactions or breakthrough viral infections after famciclovir initiation but this observation is limited by a small patient population.


CONCLUSIONS
Due to the limited data available, famciclovir appears to be a reasonable option in immunocompromised patients with a mild valacyclovir or acyclovir hypersensitivity reaction.
Department of Pharmacy, NewYork-Presbyterian Hospital, New York, NY, USA sas9128@nyp.org.
Shreya A
SA
Shah
Department of Pharmacy, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Alison
A
Gulbis
Department of Pharmacy, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Kaci
K
Wilhelm
D015075:2-Aminopurine / Q000031:analogs & derivatives* / Q000627:therapeutic use; D000212:Acyclovir / Q000009:adverse effects / Q000031:analogs & derivatives*; D000998:Antiviral Agents / Q000009:adverse effects / Q000627:therapeutic use; D004342:Drug Hypersensitivity / Q000175:diagnosis / Q000517:prevention & control*; D000077595:Famciclovir; D005260:Female; D006801:Humans; D016867:Immunocompromised Host / Q000187:drug effects; D008875:Middle Aged; D033581:Stem Cell Transplantation / Q000009:adverse effects*; D000077483:Valacyclovir; D014633:Valine / Q000009:adverse effects / Q000031:analogs & derivatives*
D000998:Antiviral Agents; D015075:2-Aminopurine; D014633:Valine; D000077483:Valacyclovir; D000077595:Famciclovir; D000212:Acyclovir
Valacyclovir hypersensitivity; acyclovir hypersensitivity; famciclovir; hematopoietic stem cell transplant; herpes simplex virus; varicella zoster virus; viral reactivations