[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Multiple sclerosis disease-modifying therapies](https://durgical.com/en/pharmacology/classes/multiple-sclerosis-disease-modifying-therapies/) › Teriflunomide

# Teriflunomide

## Multiple sclerosis disease-modifying therapies?

Multiple sclerosis disease-modifying therapies

## Pregnancy: contraindicated?

Contraindicated: teratogenic and embryolethal in animals. Women who wish to become pregnant stop it and undergo accelerated elimination first.

An oral DHODH inhibitor for relapsing multiple sclerosis; it can injure the liver and harm a fetus, and stays in the body for months.

Updated Nov 1, 2026

## Quick facts

**Group**
[Multiple sclerosis disease-modifying therapies](https://durgical.com/en/pharmacology/classes/multiple-sclerosis-disease-modifying-therapies/)

**Target**
Dihydroorotate dehydrogenase (DHODH)

**Used for**
Relapsing forms of multiple sclerosis

**Key effects**
Headache · Diarrhoea and nausea · Hair thinning

**Monitor**
Transaminases · Pregnancy test before starting

**ATC**
L04AK02

No doses: the clinician sets them by the current guideline.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Clinical What the labels mean

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## Mechanism of action

✂**Dihydroorotate dehydrogenase (DHODH)**Teriflunomide

ⓘ The figure shows teriflunomide (named A77 1726 in the crystal) bound to human dihydroorotate dehydrogenase, next to its FMN cofactor and orotate.

**Target in 3D:** Dihydroorotate dehydrogenase (DHODH). PDB structure 1D3H (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/1D3H) · Drag to rotate · pinch to zoom

Teriflunomide reversibly inhibits dihydroorotate dehydrogenase, the mitochondrial enzyme of de novo pyrimidine synthesis. The proliferation of activated T and B lymphocytes, which need new pyrimidines to divide, falls. The exact way this helps multiple sclerosis is not known but may involve fewer activated lymphocytes in the CNS.

- Teriflunomide inhibits DHODH in mitochondria
- De novo pyrimidine synthesis slows
- Activated lymphocytes proliferate less
- Fewer relapses in relapsing MS

## Indications

- Relapsing forms of multiple sclerosis [Multiple sclerosis →](https://durgical.com/en/conditions/multiple-sclerosis/)

## Adverse effects

### Common

- Headache
- Diarrhoea and nausea
- Hair thinning (alopecia)
- Raised ALT

### Serious (rare, important)

- Hepatotoxicity, including liver failure needing transplant (boxed warning)
- Embryofetal toxicity (boxed warning)
- Low white cell and platelet counts; infections including tuberculosis
- Severe skin reactions (Stevens-Johnson, toxic epidermal necrolysis, DRESS)
- Peripheral neuropathy; raised blood pressure

## Contraindications

- Pregnancy, and women who could become pregnant without effective contraception
- Severe liver impairment
- Current leflunomide treatment; hypersensitivity to teriflunomide or leflunomide

## Key interactions

**Leflunomide**
Contraindicated together

**Warfarin**
Peak INR may fall; INR is monitored closely

**Rosuvastatin and other BCRP or OATP1B1/1B3 substrates**
Higher exposure of those drugs; their doses are limited

**Oral contraceptives (ethinylestradiol, levonorgestrel)**
Higher hormone exposure; the contraceptive is chosen with care

**Other hepatotoxic drugs**
Higher risk of severe liver injury

**Live vaccines**
Not recommended

## What is monitored

- Transaminases and bilirubin within 6 months before starting; ALT at least monthly for the first 6 months
- Recent complete blood count before starting
- Pregnancy test before starting in women who could become pregnant
- Screening for latent tuberculosis
- Blood pressure at the start and during treatment

## Administration and safety

- Accelerated elimination with cholestyramine or activated charcoal is used for liver injury, severe reactions, planned pregnancy or when stopping in women who could become pregnant
- Not started during an active infection

## Pregnancy and breastfeeding

Contraindicated: teratogenic and embryolethal in animals. Women who wish to become pregnant stop it and undergo accelerated elimination first.

## Nursing care

- Confirm a negative pregnancy test and effective contraception
- Teach signs of liver injury: nausea, vomiting, abdominal pain, tiredness, loss of appetite, jaundice
- Report fever, infections, rash or numbness of hands and feet
- Explain that hair thinning is common

## Pharmacokinetics

**Absorption**
Oral, once daily

**Elimination**
Very slow: on average 8 months (up to 2 years) to reach very low levels unless cholestyramine or activated charcoal is given for 11 days

**Half-life**
Median about 18 to 19 days

## Memory aid

«TERIflunomide: TERatogen, TERrible liver, TERribly long stay»: block DHODH, then wash it out with cholestyramine.

## Test yourself

Think of the answer, then tap the question to see it.

## Which enzyme does teriflunomide inhibit?

Dihydroorotate dehydrogenase, in de novo pyrimidine synthesis.

## What are teriflunomide's two boxed warnings?

Hepatotoxicity and embryofetal toxicity.

## How is teriflunomide removed quickly from the body?

An accelerated elimination procedure with cholestyramine or activated charcoal.

## Which drug must not be combined with teriflunomide?

Leflunomide.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/pharmacology/teriflunomide/)

[More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology)

## What the labels mean

**Pregnancy: contraindicated**
Contraindicated: teratogenic and embryolethal in animals. Women who wish to become pregnant stop it and undergo accelerated elimination first.

## Connections

## Related drugs 5

- [Leflunomide](https://durgical.com/en/pharmacology/leflunomide/)
- [Colestyramine](https://durgical.com/en/pharmacology/colestyramine/)
- [Warfarin](https://durgical.com/en/pharmacology/warfarin/)
- [Dimethyl fumarate](https://durgical.com/en/pharmacology/dimethyl-fumarate/)
- [Fingolimod](https://durgical.com/en/pharmacology/fingolimod/)

## Related conditions 1

- [Multiple sclerosis](https://durgical.com/en/conditions/multiple-sclerosis/)

[← Back to the class: Multiple sclerosis disease-modifying therapies](https://durgical.com/en/pharmacology/classes/multiple-sclerosis-disease-modifying-therapies/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [DailyMed - TERIFLUNOMIDE tablet, film coated](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=c424959d-00c9-4e76-aba6-cc7464d8e903) (DailyMed (U.S. National Library of Medicine), 2026); [Teriflunomide: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a613010.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [RCSB PDB - 1D3H: HUMAN DIHYDROOROTATE DEHYDROGENASE COMPLEXED WITH ANTIPROLIFERATIVE AGENT A771726](https://www.rcsb.org/structure/1D3H) (RCSB Protein Data Bank, 2026).

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Representative model, for educational purposes only.

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License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/teriflunomide/