Dosage recommendations for adult patients with reduced renal function are provided in Table 1 [see Use in Specific Populations ( 8.5, 8.6), Clinical Pharmacology (12.3)].Data are not available for the use of valacyclovir in pediatric patients with a creatinine clearance less than 50 mL/min/1.73 m 2.
Table 1. Valacyclovir Dosage Recommendations for Adults With Renal Impairment
|Indications||Normal Dosage Regimen (Creatinine Clearance ≥ 50 mL/min)||Creatinine Clearance (mL/min)|
|Cold sores (Herpes Labialis) Do not exceed 1 day of treatment.||Two 2-gram doses taken 12 hours apart||Two 1-gram doses taken 12 hours apart||Two 500-mg doses taken 12 hours apart||500-mg single dose|
|Genital herpes: Initial episode||1 gram every 12 hours||no reduction||1 gram every 24 hours||500 mg every 24 hours|
|Genital herpes: Recurrent episode||500 mg every 12 hours||no reduction||500 mg every 24 hours||500 mg every 24 hours|
|Genital herpes: Suppressive therapy Immunocompetent patients Alternate dose for immunocompetent patients with less than or equal to 9 recurrences/year HIV-1-infected patients||1 gram every 24 hours 500 mg every 24 hours 500 mg every 12 hours||no reduction no reduction no reduction||500 mg every 24 hours 500 mg every 48 hours 500 mg every 24 hours||500 mg every 24 hours 500 mg every 48 hours 500 mg every 24 hours|
|Herpes zoster||1 gram every 8 hours||1 gram every 12 hours||1 gram every 24 hours||500 mg every 24 hours|
Patients requiring hemodialysis should receive the recommended dose of valacyclovir after hemodialysis. During hemodialysis, the half-life of acyclovir after administration of valacyclovir is approximately 4 hours. About one-third of acyclovir in the body is removed by dialysis during a 4-hour hemodialysis session.
There is no information specific to administration of valacyclovir in patients receiving peritoneal dialysis. The effect of chronic ambulatory peritoneal dialysis (CAPD) and continuous arteriovenous hemofiltration/dialysis (CAVHD) on acyclovir pharmacokinetics has been studied. The removal of acyclovir after CAPD and CAVHD is less pronounced than with hemodialysis, and the pharmacokinetic parameters closely resemble those observed in patients with end-stage renal disease (ESRD) not receiving hemodialysis. Therefore, supplemental doses of valacyclovir should not be required following CAPD or CAVHD.
Valacyclovir Tablets, USP:
• 500 mg: Each blue colored, capsule shaped, biconvex, film coated tablets debossed with ‘RDY’ on one side and ‘552’ on the other side contains 556.2 mg of valacyclovir hydrochloride equivalent to 500 mg of the free base.
• 1 gram: Each blue, film-coated, capsule-shaped, biconvex tablets, with a partial score bar on both sides debossed with “RDY” on one side and “553” on the other side contains 1.112 grams of valacyclovir hydrochloride equivalent to 1 gram of the free base.
Valacyclovir is contraindicated in patients who have had a demonstrated clinically significant hypersensitivity reaction (e.g., anaphylaxis) to valacyclovir, acyclovir, or any component of the formulation [see Adverse Reactions (6.3)].
TTP/HUS, in some cases resulting in death, has occurred in patients with advanced HIV-1 disease and also in allogeneic bone marrow transplant and renal transplant recipients participating in clinical trials of valacyclovir at doses of 8 grams per day. Treatment with valacyclovir should be stopped immediately if clinical signs, symptoms, and laboratory abnormalities consistent with TTP/HUS occur.
Cases of acute renal failure have been reported in:
• Elderly patients with or without reduced renal function. Caution should be exercised when administering valacyclovir to geriatric patients, and dosage reduction is recommended for those with impaired renal function
see Dosage and Administration (2.4), Use in Specific Populations (8.5)].
• Patients with underlying renal disease who received higher than recommended doses of valacyclovir for their level of renal function. Dosage reduction is recommended when administering valacyclovir to patients with renal impairment [ see Dosage and Administration (2.4),Use in Specific Populations (8.6)].
• Patients receiving other nephrotoxic drugs. Caution should be exercised when administering valacyclovir to patients receiving potentially nephrotoxic drugs.
• Patients without adequate hydration. Precipitation of acyclovir in renal tubules may occur when the solubility (2.5 mg/mL) is exceeded in the intratubular fluid. Adequate hydration should be maintained for all patients.
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