Yes. 25 FDA-approved labels for Leflunomide carry a boxed warning, and its subject is embryo-fetal toxicity and hepatotoxicity embryo-fetal toxicity. A boxed warning is the most serious warning the FDA requires on a prescription label. It is applied to the drug and to the situations in which it is used, not to any particular person taking it.
What the warning says
Below is how the Leflunomide warning opens on one specific label, identified underneath it. Of the 25 Leflunomide labels sampled, 7 carried materially different wordings and this was the most common, used by 9 of them.
WARNING: EMBRYO-FETAL TOXICITY and HEPATOTOXICITY Embryo-Fetal Toxicity Leflunomide is contraindicated for use in pregnant women because of the potential for fetal harm. Teratogenicity and embryo-lethality occurred in animals administered leflunomide at doses lower than the human exposure level. Exclude pregnancy before the start of treatment with leflunomide in females of reproductive potential. Advise females of reproductive potential to use effective contraception during leflunomide treatment and during an accelerated drug elimination procedure after leflunomide treatment.
LEFLUNOMIDE, A-S Medication Solutions, label version effective 08 January 2025. Opening of the warning; read the full label on DailyMed.Why the wording differs between manufacturers
There is no single official text of a boxed warning. The FDA sets what a warning must cover, and each manufacturer writes its own label within that. Of the 25 Leflunomide labels sampled for this page, 7 carried materially different wordings of the same warning, and the version quoted above was used by 9 of them.
The hazard does not change between those 7 versions. Only the sentences do, which is why a refill from a different manufacturer can carry warning text that reads differently without anything about Leflunomide or its risks having changed.
Leflunomide is dispensed under 25 current FDA labels despite this warning, which is the point worth holding onto: a boxed warning is a disclosure requirement, not a verdict. What a boxed warning does and does not mean sets out the distinction.
Common questions
Does Leflunomide have a black box warning?
Yes. 25 FDA-approved labels for Leflunomide carry a boxed warning, and its subject is embryo-fetal toxicity and hepatotoxicity embryo-fetal toxicity. A boxed warning is the strongest warning the FDA requires on a prescription label, and it is applied to the drug, not to any individual taking it.
What does the Leflunomide boxed warning say?
The wording is set by each manufacturer within FDA requirements, so it varies. In the version quoted on this page, taken from a label effective 08 January 2025, the warning concerns embryo-fetal toxicity and hepatotoxicity embryo-fetal toxicity. The full text is linked so the exact version can be read rather than summarised.
Does the Leflunomide boxed warning mean the drug is unsafe or being withdrawn?
No. It means the FDA requires the risk of embryo-fetal toxicity and hepatotoxicity embryo-fetal toxicity to be communicated prominently so prescribers weigh it explicitly. Leflunomide remains FDA-approved and is dispensed under 25 current labels. A boxed warning is a disclosure requirement, not a judgement that a drug should not be used.
Why do different pharmacies show different warning text for the same drug?
Because each manufacturer writes its own label within the FDA's requirements. Of 25 Leflunomide labels sampled here, 7 carried materially different wordings of the same warning. The hazard described is the same; the sentences are not. This is a common source of confusion when a prescription is refilled with a different manufacturer's product.
Should I stop taking Leflunomide because of this warning?
This page does not answer that and cannot. The warning about embryo-fetal toxicity and hepatotoxicity embryo-fetal toxicity is written for a prescriber deciding whether Leflunomide suits a particular patient, and stopping a prescribed medicine carries its own risks that this page knows nothing about. Raise it with the prescriber or a pharmacist, who can see the whole picture.
Where this page's information comes from
The quotation above is from one Leflunomide label, linked below by its DailyMed set identifier so the exact version can be opened rather than taken on trust. The figure of 25 labels, and the count of 7 distinct wordings among 25 sampled, were computed from the openFDA labelling API on 30 August 2026.
- LEFLUNOMIDE prescribing information, A-S Medication Solutions, effective 08 January 2025.
- openFDA drug labelling API, the source of the label counts and variant counts on this page.
Labels are revised over time. The version linked above is the one this page was written against, and a newer revision may differ. Counts reflect the labels present in openFDA on the retrieval date.