Methotrexate and anti-inflammatory painkillers such as ibuprofen

Methotrexate is used for autoimmune and inflammatory conditions. The NHS says it calms the immune system to help stop it attacking the body's own cells, which reduces the inflammation behind swollen and stiff joints in rheumatoid arthritis, thickened skin in psoriasis and bowel damage in Crohn's disease. It is also used at different doses and schedules in some cancer treatments.

The NHS is clear that methotrexate is not a painkiller. People may notice less pain as inflammation settles, but it can take up to 12 weeks after the dose has been increased to a full dose before benefits are noticed. During that time, and during flares, it is natural to want something for the pain. Over-the-counter anti-inflammatory painkillers such as ibuprofen are the obvious choice, which is exactly why the pairing needs thought.

The NHS also lists NSAIDs among the wider treatments for rheumatoid arthritis, so some people will be prescribed an anti-inflammatory painkiller by the same team that prescribes methotrexate. That is a supervised decision. The caution is aimed at the unsupervised add-on.

The NHS page on taking methotrexate with other medicines begins by stating that there are many medicines that affect the way methotrexate works. It asks you to tell your doctor, before you start, if you take any of a listed set. The first group is non-steroidal anti-inflammatory drugs like ibuprofen, or cough and cold remedies containing NSAIDs. The list goes on to include co-trimoxazole, trimethoprim or other antibiotics, diuretics such as indapamide or bendroflumethiazide, epilepsy medicines such as phenytoin or levetiracetam, theophylline, indigestion medicines such as omeprazole, and folic acid or vitamin supplements containing folic acid.

The page adds that these are not all the medicines that may affect methotrexate and sends you to the leaflet. It also advises showing the patient card, so that anyone prescribing or selling a medicine knows about the once-weekly dose.

On the page about side effects, the advice for headaches is to rest, drink plenty of water, avoid too much alcohol, not take NSAIDs such as ibuprofen, and try a painkiller such as paracetamol. Talk to your doctor if headaches last longer than a week or are severe.

The NHS wording about cough and cold remedies is a useful reminder that anti-inflammatory ingredients are not found only in packs labelled as painkillers.

• Ibuprofen and aspirin tablets, capsules and gels or sprays sold in pharmacies and supermarkets.

• Combination cold and flu products that include an anti-inflammatory ingredient alongside decongestants or caffeine.

• Soluble or dispersible tablets that are easy to take for a sore throat or a headache without reading the ingredients.

• Prescribed anti-inflammatories from another clinic, a dentist or an out-of-hours service, where the prescriber may not have your full medicine list.

Methotrexate treatment comes with a monitoring routine. According to the NHS, you will have a check-up and blood tests to look at your blood, liver and kidneys every 1 to 2 weeks when you first start, and then every 2 to 3 months once the dose is right and treatment is working well. The doctor may raise or lower your dose depending on the results, and you will usually keep a booklet recording doses and results.

The NHS lists serious side effects as rare and says to tell your doctor or call 111 immediately for yellowing of the skin or eyes, persistent cough, chest pain or breathlessness, swollen hands, ankles or feet or changes in how often you pee, a high temperature with muscle aches or sore throat, and bleeding gums, blood in pee, vomiting blood or unexplained bruising. The NHS side-effects page also lists kidney problems, shown by swollen hands, ankles or feet or changes in how often you pee, among the warning signs.

None of this means that every person on methotrexate must avoid every anti-inflammatory. It means asking before using one. A community pharmacist can look at the products on offer and say whether they contain an NSAID. Your rheumatology, dermatology or gastroenterology nurse specialist, or your GP, can say whether an anti-inflammatory fits into your own plan and how often it can be used.

In the NHS, your hospital specialist team usually starts methotrexate and your GP may take over prescribing once things are stable, with agreed blood tests. If you pay for a private consultation about your joints or skin, the same medicine list and patient card should travel with you.

Keep your weekly methotrexate stored apart from daily medicines, as the NHS advises, and call NHS 111 if you think you have taken more than prescribed or have taken it daily instead of weekly.