Two medicines, side by side
Acyclovir vs valacyclovir
Acyclovir and valacyclovir are both labeled for herpes and shingles. Drugs@FDA records approvals of acyclovir since 1982 and of valacyclovir since 1995. Pharmacies paid $0.0962 per acyclovir 400 mg tablet and $0.229 per valacyclovir HCl 500 mg tablet (NADAC, October 7, 2026); the strengths differ, so the two prices are not like for like.
Check it at the source: the acyclovir FDA label on DailyMed (effective July 24, 2026); the valacyclovir FDA label on DailyMed (effective November 12, 2025).
Highlights of the acyclovir record
Acyclovir (Zovirax) · label of July 24, 2026
Used for
From the label: indicationsHerpes Zoster Infections: Acyclovir tablets are indicated for the acute treatment of herpes zoster (shingles). Genital Herpes: Acyclovir tablets are indicated for the treatment of initial episodes and the management of recurrent episodes of genital herpes. Chickenpox: Acyclovir tablets are indicated for the treatment of chickenpox (varicella).
On the market
- Earliest approval on file
- March 29, 1982
- Generic labelers
- 66 labelers
- Pharmacy cost
- $0.0962 per tablet
Supply and safety
- Shortage
- No current entry
- Recalls
- 12
Highlights of the valacyclovir record
Valacyclovir (Valtrex) · label of November 12, 2025
Used for
From the label: indicationsVALTREX is 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 […]
On the market
- Earliest approval on file
- June 23, 1995
- Generic labelers
- 40 labelers
- Pharmacy cost
- $0.229 per tablet
Supply and safety
- Shortage
- No current entry
- Recalls
- 4
Source: FDA drug labels via openFDA (Acyclovir label of July 24, 2026, Valacyclovir label of November 12, 2025); NDC Directory, Drugs@FDA, NADAC, FDA shortages and recalls (October 8, 2026)
How do acyclovir and valacyclovir differ on the record?
Both are in FDA's class herpes zoster virus nucleoside analog dna polymerase inhibitors.
Generics: acyclovir since 1997; valacyclovir since 2007 (Drugs@FDA).
| Acyclovir | Valacyclovir | |
|---|---|---|
| Labeled for | Herpes and shingles | Herpes and shingles |
| Pharmacologic class | Herpes Simplex Virus Nucleoside Analog DNA Polymerase Inhibitor, Herpes Zoster Virus Nucleoside Analog DNA Polymerase Inhibitor, Herpesvirus Nucleoside Analog DNA Polymerase Inhibitor | Herpes Simplex Virus Nucleoside Analog DNA Polymerase Inhibitor, Herpes Zoster Virus Nucleoside Analog DNA Polymerase Inhibitor, Herpesvirus Nucleoside Analog DNA Polymerase Inhibitor |
| How it works (label) | n/a | Valacyclovir is an antiviral drug active against α-herpes viruses [see Microbiology ( 12.4 )]. |
| Half-life (label) | Mean half-life after oral doses of 300 mg/m 2 and 600 mg/m 2 in pediatric patients aged 7 months to 7 years was 2.6 hours (range 1.59 to 3.74 hours). | n/a |
| Earliest approval on file (Drugs@FDA) | March 29, 1982 | June 23, 1995 |
| First generic approved | April 22, 1997 | January 31, 2007 |
| Generic labelers (NDC) | 66 labelers | 40 labelers |
| Pharmacy cost (NADAC, each one's most listed form; strengths differ) | $0.0962 per tablet (Acyclovir 400 mg tablet) | $0.229 per tablet (Valacyclovir HCl 500 mg tablet) |
| 12-month price change | +5% | -2% |
| Boxed warning | No | No |
| Shortage now | No current entry | No current entry |
| Recalls recorded | 12 | 4 |
| FAERS reports (a report is not proof of cause; counts follow how widely a medicine is used) | 114,717 | 70,054 |
| DEA schedule | none | none |
Source: Drugs@FDA, FDA NDC Directory, CMS NADAC of October 7, 2026, FDA shortages and recalls, FAERS via openFDA (FDA files October 8, 2026)
Do their labels mention each other?
Acyclovir label, contraindicationsCONTRAINDICATIONS Acyclovir is contraindicated in patients who have had a demonstrated clinically significant hypersensitivity reaction [e.g., anaphylaxis, severe cutaneous adverse reactions (SCARs)] to acyclovir, valacyclovir, or any component of the formulation (see WARNINGS and ADVERSE REACTIONS ).
Acyclovir label, warningsAcyclovir is contraindicated in patients who have developed SCARs with the use of acyclovir or valacyclovir, or any component of the formulation (see CONTRAINDICATIONS and ADVERSE REACTIONS ).
Valacyclovir label, contraindicationsCONTRAINDICATIONS VALTREX is 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 )].
Valacyclovir label, warnings and precautionsPrecipitation of acyclovir in renal tubules may occur when the solubility (2.5 mg/mL) is exceeded in the intratubular fluid.
Source: FDA drug labels via openFDA
What next?
- Alternatives to acyclovir
- every medicine labeled for the same conditions