Frequently reported adverse events in clinical trials of VALTREX in healthy patients are listed in Tables 4 and 5.

Table 4. Incidence (%) of Adverse Events in Herpes Zoster Study Populations

Adverse Event	VALTREX 1 gram t.i.d. (n = 967)	Placebo (n = 195)
Nausea	15%	8%
Headache	14%	12%
Vomiting	6%	3%
Dizziness	3%	2%
Abdominal pain	3%	2%

Table 5. Incidence (%) of Adverse Events in Genital Herpes Study Populations

	Genital Herpes Treatment			Genital Herpes Suppression
	VALTREX 1 gram b.i.d.	VALTREX 500 mg b.i.d.	Placebo	VALTREX 1 gram q.d.	VALTREX 500 mg q.d.	Placebo
Adverse Event	(n = 1,194)	(n = 1,159)	(n = 439)	(n = 269)	(n = 266)	(n = 134)
Nausea	6%	5%	8%	11%	11%	8%
Headache	16%	15%	14%	35%	38%	34%
Vomiting	1%	<1%	<1%	3%	3%	2%
Dizziness	3%	2%	3%	4%	2%	1%
Abdominal pain	2%	1%	3%	11%	9%	6%
Dysmenorrhea	<1%	<1%	1%	8%	5%	4%
Arthralgia	<1%	<1%	<1%	6%	5%	4%
Depression	1%	0%	<1%	7%	5%	5%

Suppression of Genital Herpes in HIV-Infected Patients: In HIV-infected patients, frequently reported adverse events for VALTREX (500 mg twice daily; n = 194, median days on therapy = 172) and placebo (n = 99, median days on therapy = 59), respectively, included headache (13% vs. 8%), fatigue (8% vs. 5%), and rash (8% vs. 1%). Post-randomization laboratory abnormalities that were reported more frequently in valacyclovir subjects versus placebo included elevated alkaline phosphatase (4% vs. 2%), elevated ALT (14% vs. 10%), elevated AST (16% vs. 11%), decreased neutrophil counts (18% vs. 10%), and decreased platelet counts (3% vs. 0%).Reduction of Transmission: In a clinical study for the reduction of transmission of genital herpes, the adverse events reported by patients receiving VALTREX 500 mg once daily (n = 743) or placebo once daily (n = 741) included headache (VALTREX 29%, placebo 26%), nasopharyngitis (VALTREX 16%, placebo 15%), and upper respiratory tract infection (VALTREX 9%, placebo 10%). In this 8-month study, there were no clinically significant changes from baseline laboratory parameters in subjects receiving VALTREX compared with placebo.

Cold Sores (Herpes Labialis): In clinical studies for the treatment of cold sores, the adverse events reported by patients receiving VALTREX (n = 609) or placebo (n = 609) included headache (VALTREX 14%, placebo 10%) and dizziness (VALTREX 2%, placebo 1%). The frequencies of abnormal ALT (>2 x ULN) were 1.8% for patients receiving VALTREX 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.

Observed During Clinical Practice: The following events have been identified during post-approval use of VALTREX in clinical practice. Because they are reported voluntarily from a population of unknown size, estimates of frequency cannot be made. These events have been chosen for inclusion due to either their seriousness, frequency of reporting, causal connection to VALTREX, or a combination of these factors.

General: Facial edema, hypertension, tachycardia.

Allergic: Acute hypersensitivity reactions including anaphylaxis, angioedema, dyspnea, pruritus, rash, and urticaria.

CNS Symptoms: Aggressive behavior; agitation; ataxia; coma; confusion; decreased consciousness; dysarthria; encephalopathy; mania; and psychosis, including auditory and visual hallucinations; seizures, tremors (see PRECAUTIONS).

Eye: Visual abnormalities.

Gastrointestinal: Diarrhea.

Hepatobiliary Tract and Pancreas: Liver enzyme abnormalities, hepatitis. Renal: Elevated creatinine, renal failure.

Hematologic: Thrombocytopenia, aplastic anemia, leukocytoclastic vasculitis, TTP/HUS.

Skin: Erythema multiforme, rashes including photosensitivity, alopecia. Renal Impairment: Renal failure and CNS symptoms have been reported in patients with renal impairment who received VALTREX or acyclovir at greater than the recommended dose. Dose reduction is recommended in this patient population