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Cloxacillin Side Effects

The most commonly reported side effects of cloxacillin include drug interaction, nausea, and acute kidney injury, based on 626 FDA adverse event reports from 2004 to 2025. 5.1% of reports found the drug to be ineffective.

Cloxacillin side effects

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

1
Drug Interaction8.0%50
2
Nausea6.1%38
3
Acute Kidney Injury5.6%35
4
Drug Ineffective5.1%32
5
Rash5.0%31
6
Off Label Use3.8%24
7
Diarrhoea3.0%19
8
Dyspnoea3.0%19
9
Renal Failure2.9%18
10
Neutropenia2.9%18
11
Malaise2.7%17
12
Gastrointestinal Haemorrhage2.6%16
13
Fatigue2.4%15
14
Pyrexia2.4%15
15
Blood Pressure Decreased2.4%15

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

Report severity

95.7%Serious599 reports
49.5%Hospitalizations310 reports
15.7%Fatal98 reports

Seriousness is determined by the reporter, not by OpenClaim.

Cloxacillin drug interactions

Other drugs that appear in adverse event reports alongside cloxacillin. 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
Gentamicin-sulfate10.5%66
2
Acetaminophen6.7%42
3
Tacrolimus5.8%36
4
Pantoprazole-sodium5.0%31
5
Vancomycin5.0%31
6
Allopurinol4.6%29
7
Ciprofloxacin4.2%26
8
Furosemide4.2%26
9
Metformin4.2%26
10
Prednisolone4.0%25
11
Enoxaparin-sodium3.8%24
12
Mycophenolate3.8%24
13
Meropenem3.7%23
14
Atorvastatin-calcium3.7%23
15
Warfarin3.5%22

Taken alongside

1
Acetaminophen17.9%112
2
Omeprazole8.5%53
3
Furosemide7.7%48
4
Atorvastatin-calcium6.9%43
5
Albuterol6.1%38
6
Aspirin6.1%38
7
Oxycodone5.9%37
8
Prednisolone5.3%33
9
Pantoprazole-sodium5.3%33
10
Amlodipine4.8%30
11
Lansoprazole4.8%30
12
Loperamide-hydrochloride4.8%30
13
Amoxicillin4.6%29
14
Enoxaparin-sodium4.6%29
15
Levothyroxine-sodium4.5%28

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 cloxacillin side effects

48.1% of cloxacillin adverse event reports involve female patients and 44.7% involve male patients. The largest age group is adult at 48%. These figures reflect who reports side effects, not underlying risk.

Sex

Female48.1%
Male44.7%
Unknown7.2%

Age group

< 21.9%
2–113.2%
12–172.3%
18–6447.8%
65+44.8%

What is cloxacillin used for

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

AbscessAbscess LimbAcute TonsillitisAllergy TestAntibiotic ProphylaxisArthritis BacterialArthritis InfectiveAbscessAcute EndocarditisAnti-infective TherapyAntibiotic TherapyArthritis BacterialBacteraemiaBacterial InfectionBlister

Showing 15 of 110 indications

Cloxacillin brand names and reporting trend

Cloxacillin is sold under the brand name Tegopen.

Brand names

Tegopen684

Quarterly reports (20042025)

20052010201520202025

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

Taking cloxacillin with another medication?

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