Drug	Dosage	Decrease in recurrence rate (percentage)	Suggested for use in patients with ≥ 6 recurrences per year	Cost (generic)*
Acyclovir (Zovirax)	400 mg twice daily	78 to 79	Yes	$5 (4)
Famciclovir (Famvir)	250 mg twice daily	79	Yes	7
Valacyclovir (Valtrex)	1 g once daily	78 to 79	Yes	4
	250 mg twice daily†‡	78 to 79	Yes	3
	500 mg once daily	71	No	3
	250 mg once daily†‡	54	No	2