Critical Safety Point — Weekly, Not Daily
Methotrexate for rheumatoid arthritis and psoriasis is taken ONCE PER WEEK — not daily. Accidental daily dosing is a well-documented, sometimes fatal medication error. Always double-check your dosing schedule with your pharmacist and use a dosing calendar or reminder.Why Folic Acid Is Given
Folic acid (usually 5mg once weekly, on a different day from methotrexate) reduces methotrexate's side effects — nausea, mouth ulcers, hair thinning, and liver toxicity — without reducing its effectiveness for arthritis or psoriasis.Monitoring Schedule
| Test | Frequency |
|---|---|
| FBC | Every 1-2 weeks initially, then every 2-3 months once stable |
| Liver function tests | Same schedule as FBC |
| Kidney function (creatinine) | Same schedule |
| Chest X-ray | Baseline before starting (methotrexate can rarely cause lung inflammation) |
Common Side Effects
- Nausea (reduced by folic acid and taking with food)
- Mouth ulcers
- Fatigue the day after taking the dose
- Hair thinning (usually mild)
- Increased infection risk (immune suppression)
Serious Warning Signs — Seek Urgent Medical AdviceSore throat, unexplained bruising or bleeding, mouth ulcers becoming severe, shortness of breath, or persistent cough can indicate bone marrow suppression or lung toxicity — contact your rheumatology team or GP urgently and have blood tests checked.
Alcohol and MethotrexateMethotrexate and alcohol both affect the liver, so most guidelines recommend limiting alcohol significantly (some suggest avoiding entirely) while on methotrexate to reduce the risk of liver damage.
Is methotrexate for arthritis the same as chemotherapy?
Methotrexate is the same drug used at much higher doses for cancer treatment, but the low weekly doses used for rheumatoid arthritis and psoriasis work differently (anti-inflammatory/immune-modulating) and have a much better safety profile at these doses.
Can I get pregnant while taking methotrexate?
No — methotrexate is teratogenic (causes birth defects) and must be stopped at least 3-6 months before trying to conceive, for both women AND men taking the medication, as it can also affect sperm.
Do I need vaccinations while on methotrexate?
Live vaccines are generally avoided while on methotrexate due to immune suppression. Annual flu vaccine and pneumococcal vaccine are recommended, as these are inactivated and safe.
Medical Disclaimer: This page is for general education only and does not replace professional medical advice. Always consult a qualified healthcare provider.