Injecting methotrexate at home

Key points

• 01Once a week is the entire safety story. For rheumatoid arthritis, psoriasis and similar conditions, this medication is given once weekly. Daily administration by mistake has caused serious and fatal harm, which is why it is treated as a high-alert medication in hospital safety systems.
• 02Write the day down and defend it. Pick a fixed weekday, set a recurring reminder, and record every dose. The record is not paperwork, it is the thing that answers the question of whether this week's dose has already been given when two people share the caring.
• 03Never double up for a missed dose. If a dose is missed, contact your prescriber or pharmacist and follow what they tell you. Taking two doses close together is exactly the pattern the safety warnings exist to prevent, and it is not a judgement call to make at home.
• 04Injection is not the same as tablets. A study in Rheumatology published in 2021 compared the effectiveness and tolerability of oral and subcutaneous methotrexate in rheumatoid arthritis, and a 2021 paper in Arthritis Care and Research looked at the safety and tolerability of the subcutaneous route in routine practice. The route is a clinical decision.
• 05Folic acid is usually part of the plan. Many prescribers add folic acid or folinic acid to reduce side effects, on a schedule that deliberately avoids the injection day. Take it exactly as prescribed. If nobody has mentioned it to you, that is a question worth asking.
• 06Blood tests are not optional. Regular monitoring of blood counts, liver and kidney function is part of treatment. Keeping those appointments is as much a part of the medication as the injection itself, and missing them is how problems get found late.
• 07It is a cytotoxic medication and is handled accordingly. Keep it in its packaging, avoid skin contact with the liquid, wash any skin it touches, and keep it well away from children. Anyone pregnant or breastfeeding should not handle the devices at all.
• 08Pregnancy is a hard stop. The labelling carries serious warnings about harm in pregnancy for non-cancer uses. Contraception, pregnancy planning and the timing of any attempt to conceive are prescriber conversations that happen before treatment starts, for both partners.
• 09Other medicines interact more than you would expect. Some common painkillers and antibiotics interact with this drug. Do not start anything new, including over-the-counter medicines and supplements, without checking with your pharmacist. Our post on injecting with other medications covers how to keep the list current.
• 10Alcohol comes up at every review for a reason. Liver effects are one of the monitored risks, which is why prescribers ask about alcohol at each review. Answer honestly rather than defensively. The question is about adjusting monitoring, not about disapproval.
• 11Rotate sites and skip damaged skin. Use the abdomen away from the navel and the front of the thigh, and change the spot every week. Avoid psoriasis plaques, bruises and hardened areas, which absorb unpredictably and hurt more.
• 12Learn the red flags before your first dose. Mouth ulcers, sore throat with fever, unusual bruising, a new dry cough or breathlessness, and yellowing of the skin all have specific significance on this medication. Read them once now rather than searching for them at 2am.

Pre-injection checklist

• ✓This medication is taken once a week for inflammatory conditions, not once a day. Confirm your day and write it down. Taking it daily by mistake is the error every safety warning about this drug is built around.
• ✓Keep the instructions for use that came with your device. Auto-injectors and prefilled syringes are handled differently, and brands differ from one another.
• ✓Check the label, the strength and the expiry date, and look at the liquid. Do not use a device that is cloudy, discoloured, contains particles, or has been dropped.
• ✓This medication can cause serious harm in pregnancy. Contraception and pregnancy planning are conversations to have with your prescriber before you start, not after.
• ✓This is a technique reference, not medical advice. Your dose, your day, your monitoring and your folic acid are set by your prescriber.

Step-by-step guide

1. 1

   Confirm the day before you touch the device

   Check your record or your calendar and confirm that today is your injection day and that this week's dose has not already been given. This sounds excessive until you know that the classic serious error with this medication is repeat dosing.

   Pro tip

   Always check the fluid is clear and colourless before injection.
2. 2

   Wash your hands and set up

   Wash with soap and water for at least 20 seconds and dry on a clean towel. Lay out the device, an alcohol pad and gauze on a clean surface, and open the sharps container before you start so the used device has somewhere to go immediately.

   Pro tip

   Always check the fluid is clear and colourless before injection.
3. 3

   Check the device and the liquid

   Confirm the medication name and the strength against your prescription, check the expiry date, and look at the liquid through the window. Set aside anything cloudy, discoloured, containing particles, cracked or dropped, and call the pharmacy.

   Pro tip

   Always check the fluid is clear and colourless before injection.
4. 4

   Handle it carefully and avoid skin contact

   This is a cytotoxic medication. Keep it in its packaging until you are ready, do not open a device that is leaking, and wash any skin that the liquid touches with soap and water. Anyone who is pregnant or breastfeeding should not handle it.

   Pro tip

   Always check the fluid is clear and colourless before injection.
5. 5

   Let it reach room temperature if your leaflet says to

   Some presentations are stored at room temperature and some are not. Follow the storage and preparation instruction in your own leaflet rather than a habit carried over from another injectable.

   Pro tip

   Always check the fluid is clear and colourless before injection.
6. 6

   Choose a site on the abdomen or thigh

   The usual subcutaneous sites for these devices are the abdomen, keeping about 5 cm clear of the navel, and the front of the thigh. Rotate each week. Our rotating injection sites guide covers a pattern you can keep to without thinking.

   Pro tip

   Always check the fluid is clear and colourless before injection.
7. 7

   Skip skin that is not healthy

   Avoid skin that is tender, bruised, scarred, hardened, or affected by a psoriasis plaque. Move to a different area rather than a nearby centimetre. Our post on where not to inject on the skin explains what changes absorption.

   Pro tip

   Always check the fluid is clear and colourless before injection.
8. 8

   Clean the skin and let it dry

   Wipe the chosen spot with an alcohol pad in one direction and let it air-dry for at least ten to fifteen seconds, without fanning or blowing. Injecting through wet alcohol is the most common avoidable cause of stinging.

   Pro tip

   Always check the fluid is clear and colourless before injection.
9. 9

   Give the injection as your device directs

   For an auto-injector, remove the cap, press the device flat against the skin and hold until the indicator shows the dose is complete. For a prefilled syringe, pinch a fold of skin, insert at the angle your leaflet specifies and push the plunger slowly.

   Pro tip

   Always check the fluid is clear and colourless before injection.
10. 10

    Dispose immediately and record it

    Put the whole device in the sharps container without recapping. Press with gauze if it bleeds, without rubbing. Write down the date, the site and the side, and tick this week off so nobody can give a second dose by accident.

    Pro tip

    Always check the fluid is clear and colourless before injection.

After the injection

• Press a gauze square on the site for a few seconds without rubbing.
• Put the whole device in the sharps container immediately, without recapping.
• Record the date, the site and the side, and mark the week as done.
• Take folic acid exactly as prescribed, on the days your prescriber specified rather than the injection day.
• Wash your hands after handling the device, and wash any skin the liquid touched with soap and water.

Common mistakes

Frequently asked questions

Sources

1. DailyMed. OTREXUP (methotrexate) injection, solution, for subcutaneous use.
2. MedlinePlus. Methotrexate: patient drug information.
3. Effectiveness and tolerability of oral vs subcutaneous methotrexate in patients with rheumatoid arthritis. Rheumatology (Oxford), 2021.
4. Safety and Tolerability of Subcutaneous Methotrexate in Routine Clinical Practice. Arthritis Care and Research, 2021.
5. NHS. Methotrexate: medicines information for patients.