Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared with rates in the clinical trials of another drug and may not reflect the rates observed in practice.
Cold Sores (Herpes Labialis): In clinical studies for the treatment of cold sores, the adverse reactions reported by patients receiving valacyclovir hydrochloride 2 grams twice daily (n = 609) or placebo (n = 609) for 1 day, respectively, included headache (14%, 10%) and dizziness (2%, 1%). The frequencies of abnormal ALT (>2 x ULN) were 1.8% for patients receiving valacyclovir hydrochloride compared with 0.8% for placebo. Other laboratory abnormalities (hemoglobin, white blood cells, alkaline phosphatase, and serum creatinine) occurred with similar frequencies in the 2 groups.
Genital Herpes: Initial Episode: In a clinical study for the treatment of initial episodes of genital herpes, the adverse reactions reported by ≥5% of patients receiving valacyclovir hydrochloride 1 gram twice daily for 10 days (n = 318) or oral acyclovir 200 mg 5 times daily for 10 days (n = 318), respectively, included headache (13%, 10%) and nausea (6%, 6%). For the incidence of laboratory abnormalities see Table 2.
Recurrent Episodes: In 3 clinical studies for the episodic treatment of recurrent genital herpes, the adverse reactions reported by ≥5% of patients receiving valacyclovir hydrochloride 500 mg twice daily for 3 days (n = 402), valacyclovir hydrochloride 500 mg twice daily for 5 days (n = 1,136) or placebo (n = 259), respectively, included headache (16%, 11%, 14%) and nausea (5%, 4%, 5%). For the incidence of laboratory abnormalities see Table 2.
Suppressive Therapy: Suppression of Recurrent Genital Herpes in Immunocompetent Adults: In a clinical study for the suppression of recurrent genital herpes infections, the adverse reactions reported by patients receiving valacyclovir hydrochloride 1 gram once daily (n = 269), valacyclovir hydrochloride 500 mg once daily (n = 266), or placebo (n = 134), respectively, included headache (35%, 38%, 34%), nausea (11%, 11%, 8%), abdominal pain (11%, 9%, 6%), dysmenorrhea (8%, 5%, 4%), depression (7%, 5%, 5%), arthralgia (6%, 5%, 4%), vomiting (3%, 3%, 2%), and dizziness (4%, 2%, 1%). For the incidence of laboratory abnormalities see Table 2.
Suppression of Recurrent Genital Herpes in HIV-Infected Patients: In HIV-infected patients, frequently reported adverse reactions for valacyclovir hydrochloride (500 mg twice daily; n = 194, median days on therapy = 172) and placebo (n = 99, median days on therapy = 59), respectively, included headache (13%, 8%), fatigue (8%, 5%), and rash (8%, 1%). Post-randomization laboratory abnormalities that were reported more frequently in valacyclovir subjects versus placebo included elevated alkaline phosphatase (4%, 2%), elevated ALT (14%, 10%), elevated AST (16%, 11%), decreased neutrophil counts (18%, 10%), and decreased platelet counts (3%, 0%), respectively.
Reduction of Transmission: In a clinical study for the reduction of transmission of genital herpes, the adverse reactions reported by patients receiving valacyclovir hydrochloride 500 mg once daily (n = 743) or placebo once daily (n = 741), respectively, included headache (29%, 26%), nasopharyngitis (16%, 15%), and upper respiratory tract infection (9%, 10%).
Herpes Zoster: In 2 clinical studies for the treatment of herpes zoster, the adverse reactions reported by patients receiving valacyclovir hydrochloride 1 gram 3 times daily for 7 to 14 days (n = 967) or placebo (n = 195), respectively, included nausea (15%, 8%), headache (14%, 12%), vomiting (6%, 3%), dizziness (3%, 2%), and abdominal pain (3%, 2%). For the incidence of laboratory abnormalities see Table 2.
Table 2. Incidence (%) of Laboratory Abnormalities in Herpes Zoster and Genital Herpes Study Populations
a Data were not collected prospectively. LLN = Lower limit of normal. ULN = Upper limit of normal.
|
Laboratory Abnormality
| Herpes Zoster
| Genital Herpes Treatment
| Genital Herpes Suppression
|
Valacyclovir Hydrochloride 1 gram 3 times daily (n = 967)
| Placebo (n = 195)
| Valacyclovir Hydrochloride 1 gram twice daily (n = 1,194)
| Valacyclovir Hydrochloride 500 mg twice daily (n = 1,159)
| Placebo (n = 439)
| Valacyclovir Hydrochloride 1 gram once daily (n = 269)
| Valacyclovir Hydrochloride 500 mg once daily (n = 266)
| Placebo (n =134)
|
Hemoglobin (<0.8 x LLN)
White blood cells (<0.75 x LLN)
Platelet count (<100,000/mm3)
AST (SGOT) (>2 x ULN)
Serum creatinine (>1.5 x ULN) | 0.8%
1.3%
1%
1%
0.2%
| 0%
0.6%
1.2%
0%
0%
| 0.3%
0.7%
0.3%
1%
0.7%
| 0.2%
0.6%
0.1%
a
0%
| 0%
0.2%
0.7%
0.5%
0%
| 0%
0.7%
0.4%
4.1%
0%
| 0.8%
0.8%
1.1%
3.8%
0%
| 0.8%
1.5%
1.5%
3%
0%
|