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Nafcillin Side Effects

The most commonly reported side effects of nafcillin include renal failure acute, acute kidney injury, and drug interaction, based on 922 FDA adverse event reports from 2004 to 2025. 5.7% of reports found the drug to be ineffective.

Nafcillin side effects

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

1
Renal Failure Acute6.1%56
2
Drug Ineffective5.7%53
3
Acute Kidney Injury5.3%49
4
Drug Interaction3.6%33
5
Hypokalaemia3.4%31
6
Renal Failure3.1%29
7
Pyrexia3.1%29
8
Rash3.1%29
9
Rash3.0%28
10
Pain2.9%27
11
Tubulointerstitial Nephritis2.6%24
12
Anxiety2.5%23
13
Drug Hypersensitivity2.4%22
14
Diarrhoea2.3%21
15
Injury2.2%20

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

Report severity

84.5%Serious779 reports
51.2%Hospitalizations472 reports
11.9%Fatal110 reports

Seriousness is determined by the reporter, not by OpenClaim.

Nafcillin drug interactions

Other drugs that appear in adverse event reports alongside nafcillin. 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
Vancomycin9.4%87
2
Daptomycin5.6%52
3
Cefazolin-sodium4.0%37
4
Gentamicin-sulfate4.0%37
5
Tobramycin3.5%32
6
Teduglutide3.1%29
7
Ceftriaxone-sodium3.0%28
8
Ampicillin2.7%25
9
Cefepime-hydrochloride2.7%25
10
Aprotinin2.2%20
11
Prednisone2.1%19
12
Rifampin2.1%19
13
Azithromycin2.1%19
14
Warfarin1.5%14
15
Piperacillin1.5%14

Taken alongside

1
Vancomycin15.9%147
2
Furosemide10.3%95
3
Acetaminophen9.5%88
4
Heparin6.5%60
5
Aspirin6.1%56
6
Insulin5.9%54
7
Cefazolin-sodium5.3%49
8
Warfarin4.8%44
9
Gentamicin-sulfate4.8%44
10
Oxycodone4.6%42
11
Fluconazole4.6%42
12
Potassium-chloride4.6%42
13
Metoprolol4.2%39
14
Midazolam4.0%37
15
Amlodipine3.8%35

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 nafcillin side effects

29.2% of nafcillin adverse event reports involve female patients and 55.7% involve male patients. The largest age group is adult at 54%. These figures reflect who reports side effects, not underlying risk.

Sex

Female29.2%
Male55.7%
Unknown15.1%

Age group

< 24.7%
2–115.0%
12–173.7%
18–6454.4%
65+32.2%

What is nafcillin used for

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

AbscessAbscess Soft TissueAcute EndocarditisAcute Myeloid LeukaemiaAcute Respiratory FailureAntibiotic ProphylaxisAntibiotic TherapyArthritis BacterialArthritis InfectiveAntibiotic TherapyArthritis InfectiveBacteraemiaBacterial InfectionBacteraemiaCardiovascular Disorder

Showing 15 of 127 indications

Nafcillin brand names and reporting trend

Nafcillin is sold under the brand name Unipen In Plastic Container.

Brand names

Unipen In Plastic Container1,081

Quarterly reports (20042025)

20052010201520202025

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

Taking nafcillin with another medication?

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