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Penciclovir Side Effects

The most commonly reported side effects of penciclovir include fatigue, headache, and diarrhoea, based on 356 FDA adverse event reports from 2004 to 2025. 11.0% of reports found the drug to be ineffective.

Penciclovir side effects

Percentages show how often each reaction appears relative to total reports for penciclovir.

1
Drug Ineffective11.0%39
2
Fatigue7.0%25
3
Headache6.7%24
4
Diarrhoea5.9%21
5
Chronic Kidney Disease5.6%20
6
Pain5.3%19
7
Cough5.3%19
8
Hypertension4.8%17
9
Back Pain4.2%15
10
Nausea4.2%15
11
Acute Kidney Injury3.9%14
12
Renal Failure3.9%14
13
Vomiting3.7%13
14
Pain In Extremity3.7%13
15
Off Label Use3.7%13

These are voluntary reports and do not establish that penciclovir caused these reactions.

Report severity

62.1%Serious221 reports
26.4%Hospitalizations94 reports
7.3%Fatal26 reports

Seriousness is determined by the reporter, not by OpenClaim.

Penciclovir drug interactions

Other drugs that appear in adverse event reports alongside penciclovir. Drugs flagged as a suspected cause appear in the first column. Drugs taken at the same time but not suspected appear in the second.

Also suspected

1
Sodium-oxybate6.2%22
2
Omeprazole5.3%19
3
Esomeprazole4.5%16
4
Prednisone3.7%13
5
Pantoprazole-sodium3.7%13
6
Lansoprazole3.4%12
7
Methylprednisolone3.1%11
8
Mycophenolate3.1%11
9
Drospirenone2.5%9
10
Ethinyl-estradiol2.5%9
11
Rofecoxib2.2%8
12
Rituximab2.2%8
13
Etanercept2.2%8
14
Lenalidomide2.2%8
15
Valacyclovir-hydrochloride2.0%7

Taken alongside

1
Acetaminophen32.0%114
2
Albuterol25.3%90
3
Ergocalciferol22.5%80
4
Aspirin18.8%67
5
Fluticasone16.9%60
6
Omeprazole16.6%59
7
Levothyroxine-sodium16.0%57
8
Prednisone16.0%57
9
Hydrocodone13.8%49
10
Gabapentin13.8%49
11
Oxycodone13.5%48
12
Acyclovir13.5%48
13
Ibuprofen13.2%47
14
Atorvastatin-calcium12.9%46
15
Cyanocobalamin12.4%44

Co-occurrence in adverse event reports does not establish a drug interaction. Patients often take multiple medications, and these lists reflect prescribing patterns rather than causal relationships. Consult a healthcare provider about potential drug interactions.

Who reports penciclovir side effects

69.4% of penciclovir adverse event reports involve female patients and 25.0% involve male patients. The largest age group is adult at 64%. These figures reflect who reports side effects, not underlying risk.

Sex

Female69.4%
Male25.0%
Unknown5.6%

Age group

< 20.0%
2–110.4%
12–170.0%
18–6464.4%
65+35.1%

What is penciclovir used for

Conditions and purposes for which patients were taking penciclovir when the adverse event was reported.

AcneAntiviral TreatmentAntifungal ProphylaxisAntiviral ProphylaxisAntiviral TreatmentChapped LipsDrug Use For Unknown IndicationEncephalitis ViralGenital HerpesGlossodyniaHepatitisHepatitis CHerpes SimplexHerpes Virus InfectionHerpes Zoster

Showing 15 of 45 indications

Penciclovir brand names and reporting trend

Penciclovir is sold under the brand name Penciclovir.

Brand names

Penciclovir89

Quarterly reports (20042025)

20052010201520202025

An upward trend reflects increased FAERS reporting overall, not necessarily increased risk.

Taking penciclovir with another medication?

Ask OpenClaim about your specific drug combination. Get a sourced report using FDA data, drug labels, and medical literature.