Methicillin: uses, dosing, side effects & brands
Methicillin is a medicine sold in the U.S. under one brand. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
Key facts
- Available as
- Injectable
- Sold as
- Staphcillin
- Prescription?
- Prescription only
- Generic available?
- Not in our catalog
Every methicillin product we track (1)
Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
Only one: Staphcillin.
Methicillin and breastfeeding
From LactMed, the US National Library of Medicine’s Drugs and Lactation Database — quoted, not rewritten.
Full LactMed record for methicillin: levels in milk, effects in breastfed infants, and the drugs it would consider insteadAmounts of methicillin ingested by the infant in breastmilk are small and would not be expected to cause any adverse effects. Occasionally disruption of the infant's gastrointestinal flora, resulting in diarrhea or thrush have been reported with penicillins, but these effects have not been adequately evaluated. Methicillin is acceptable in nursing mothers.
National Institute of Child Health and Human Development, record revised November 15, 2024. LactMed states its information is not a substitute for professional judgement.
What people report to the FDA about methicillin
The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 2 reports naming methicillin, and the FDA flagged 100% of those reports as serious. The effects reported most often — leaving out reports about overdose, misuse or the condition being treated, which dominate the raw list for common medicines:
- chronic myeloid leukaemia1 reports
- pneumonia1 reports
- second primary malignancy1 reports
Read these as a signal, not a rate. A report does not mean methicillin caused the effect — anyone can file one, and many describe people taking several medicines for several conditions. Crucially there is no denominator: FAERS does not record how many people took the drug, so these counts cannot be turned into “X% of patients” — a bigger number often just means a more widely used or more talked-about drug. Duplicates exist, and publicity drives reporting. For what is actually established, read the FDA label section above.
Source: openFDA drug/event (FAERS), retrieved July 25, 2026.
Related calculators
Frequently asked questions
Can you take methicillin with other medicines?
It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run methicillin against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What forms does methicillin come in?
Across the brands we track, methicillin is currently marketed as injectable, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.
Is there a generic methicillin?
We do not currently list a generic-labelled methicillin product. That does not always mean none exists — it means none appears under a generic name in the FDA data we track. Ask your pharmacist.
Cite this page
- APA
- pharmaranks. (2026, July 24). Methicillin: uses, dosing, side effects & brands. https://pharmaranks.com/drugs/methicillin
- MLA
- “Methicillin: uses, dosing, side effects & brands.” pharmaranks, 24 July 2026, https://pharmaranks.com/drugs/methicillin.
We summarise public FDA and NIH sources — for a clinical claim, cite the primary source we link to as well.
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.
Read the full FDA label for methicillin on DailyMed (NIH) ↗.