Methotrexate Safety: For Arthritis and Psoriasis, Take It Once a Week

Published October 1, 2026

Methotrexate is an important medicine used to treat arthritis, psoriasis (skin condition), and some cancers. If you take methotrexate for arthritis, psoriasis, or certain other non-cancerous conditions, take it exactly as prescribed, which is usually once a week. When methotrexate is used to treat certain cancers, you may need to take it every day for a short period of time (every day for about 3 to 5 days in a row). Taking this medicine every day by mistake for arthritis or skin problems is very dangerous. It can make you very sick or even cause death in just a few days.

How Mistakes Happen

Most prescription medicines that are ordered by a doctor are taken every day. So, taking medicine daily becomes more routine. Taking methotrexate once each week varies from the routine. This can result in mistakes, especially if you take other medicines on a daily basis.  

The following case is an example of how taking methotrexate daily instead of weekly led to a tragic error.

An older person with multiple health problems received a prescription for methotrexate to treat psoriasis. The doctor wanted them to take 2 tablets once a week.

The person’s primary language was Japanese. They wrote down the instructions in Japanese as, “take 2 tablets daily,” instead of weekly. They took this dose for 6 days. This caused serious side effects including mouth sores, low blood counts, and breathing problems. They were admitted to the hospital, and their condition did not improve. They died 10 days later.

Why Take It Only Once a Week?

When used for arthritis or skin problems, taking methotrexate once a week helps slow cell growth and reduces the skin changes. It gives your body time to rest.

Taking methotrexate too often can cause the medicine to build up in your body, which can seriously damage healthy cells and organs.

Warning Signs of Overdose

Methotrexate can cause side effects, even if it is taken as directed. However, the items listed below may be early warning signs that something is not right:

• Mouth sores: Painful sores inside your mouth, on your tongue or gums
• Fever or chills: Feeling hot, cold, or weak
• Easily bruise or bleed: Bleeding gums, nosebleeds, or sudden bruises
• Bad stomach pain: Throwing up or severe diarrhea

Here’s what you can do:

If you or a family member are prescribed methotrexate to treat a skin condition, follow these recommendations:

1. ‍Pick one "Methotrexate Day": Choose one day of the week to take your medicine—such as every Tuesday. Write it on your calendar or set a reminder on your phone.
2. ‍Keep the medicine in the original container: Do not put methotrexate in a daily pillbox with your other medicines. Keep it separate so you only take it once a week.
3. ‍Check the bottle at the pharmacy: When picking up your prescription at the pharmacy, open the package and read the label before you leave the pharmacy. If it says, "take daily," talk to the pharmacist right away. Always ask to talk to the pharmacist when picking up prescriptions, especially new prescriptions.
4. ‍Ask for labels in your primary language: If you do not read English well, ask the pharmacy to print the directions in your primary language.
5. ‍Ask for an interpreter: Always ask your doctor or pharmacist for a trained medical interpreter to explain your medicine in your primary language. Translation apps or family members may make mistakes with important medical information.
6. ‍When in doubt, ask: If you are confused, stop! Contact your doctor or pharmacist before taking any medicine if you do not understand the instructions.
7. ‍Seek medical help: If you took methotrexate more than once a week, contact your doctor immediately or go to the nearest hospital emergency department.

For more tips on how to take methotrexate safely, click here.