Valacyclovir Hydrochloride

Clinical summary

Indications and usage Valacyclovir tablets are a deoxynucleoside analogue DNA polymerase inhibitor indicated for: Adult Patients ( 1.1 ) Cold Sores (Herpes Labialis) Genital Herpes Treatment in immunocompetent patients (initial or recurrent episode) Suppression in immunocompetent or HIV-1–infected patients Reduction of transmission Herpes Zoster Pediatric Patients ( 1.2 ) Cold Sores (Herpes Labialis) Chickenpox Limitations of Use ( 1.3 ) The efficacy and safety of valacyclovir tablets have not been established in immunocompromised patients other than for the suppression of genital herpes in HIV-1–infected patients. Standard dosing Valacyclovir tablets may be given without regard to meals. Valacyclovir oral suspension (25 mg/mL or 50 mg/mL) may be prepared extemporaneously from 500-mg valacyclovir tablets for use in pediatric patients for whom a solid dosage form is not appropriate [see Dosage and Administration (2.3) ] . Contraindications Valacyclovir tablets are contraindicated in patients who have had a demonstrated clinically significant hypersensitivity reaction [e.g., anaphylaxis, severe cutaneous adverse reactions (SCARs)] to valacyclovir, acyclovir, or any component of the formulation [see Warnings and Precautions (5.4) , Adverse Reactions (6.3) ] . Key warnings Thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS): Has occurred in patients with advanced HIV-1 disease and in allogenic bone marrow transplant and renal transplant patients receiving 8 grams per day of valacyclovir tablets in clinical trials. Discontinue treatment if clinical symptoms and laboratory findings consistent with TTP/HUS occur. ( 5.1 ) Acute renal failure: May occur in elderly patients (with or without reduced renal function), patients with underlying renal disease who receive higher-than-recommended doses of valacyclovir tablets for their level of renal function, patients who receive concomitant nephrotoxic drugs, or inadequately hydrated patients. Use with caution in elderly patients and reduce dosage in patients with renal impairment. ( 2.4 , 5.2 ) Central nervous system adverse reactions (e.g., agitation, hallucinations, confusion, and encephalopathy): May occur in both adult and pediatric patients (with or without reduced renal function) and in patients with underlying renal disease who receive higher-than-recommended doses of valacyclovir tablets for their level of renal function. Elderly patients are more likely to have central nervous system adverse reactions. Use with caution in elderly patients and reduce dosage in patients with renal impairment. ( 2.4 , 5.3 ) Severe cutaneous adverse reactions (SCARs): Including acute generalized exanthematous pustulosis (AGEP), drug reaction with eosinophilia and systemic symptoms (DRESS), toxic epidermal necrolysis (TEN), and Stevens-Johnson syndrome (SJS) have been reported during the postmarketing experience with valacyclovir. Discontinue valacyclovir tablets immediately if a painful rash with mucosal involvement or a progressive severe rash develops, and closely monitor clinical status. ( 5.4 ) Drug interactions No clinically significant drug-drug or drug-food interactions with valacyclovir tablets are known [see Clinical Pharmacology (12.3) ]. Pregnancy guidance Clinical data over several decades with valacyclovir and its metabolite, acyclovir, in pregnant women, have not identified a drug associated risk of major birth defects. There are insufficient data on the use of valacyclovir regarding miscarriage or adverse maternal or fetal outcomes (see Data ) . There are risks to the fetus associated with untreated herpes simplex during pregnancy (see Clinical Considerations ). In animal reproduction studies, no evidence of adverse developmental outcomes was observed with valacyclovir when administered to pregnant rats and rabbits at system exposures (AUC) 4 (rats) and 7 (rabbits) times the human exposure at the maximum recommended human dose (MRHD) (see Data ) . The estimated background risk of major birth defects and miscarriage for the indicated populations is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.