GPAtlas🧭 When to suspect toxicity (and the shared-care role)
Disease-modifying anti-rheumatic drugs (DMARDs) are specialist-initiated immunomodulators used in autoimmune and inflammatory disease – rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, SLE and connective-tissue disease, vasculitis, juvenile idiopathic arthritis, psoriasis, and inflammatory bowel disease. They control the disease process rather than just symptoms, but every one of them carries a risk of bone-marrow suppression, hepatotoxicity, infection, and (for some) organ-specific toxicity, which is why structured monitoring is mandatory.
In primary care the GP almost always meets these drugs through a shared-care agreement: rheumatology (or dermatology/gastroenterology) initiates, stabilises and retains overall responsibility, then asks the GP to continue prescribing and to perform the agreed blood monitoring. The single golden rule of that contract is simple – no satisfactory, up-to-date monitoring means no prescription. Never issue a repeat if the bloods are overdue, missing, or abnormal.
The two core GP skills are therefore safe shared-care monitoring and recognising toxicity. Suspect an adverse effect whenever a patient on a DMARD presents with infection, signs of marrow suppression (unexplained bruising, bleeding, sore throat, mouth ulcers), liver toxicity (jaundice, nausea), or respiratory symptoms (new cough or breathlessness).
| DMARD | Routine bloods (per local protocol) | Key toxicities & cautions |
|---|---|---|
| Methotrexate | FBC, U&E, LFT | Myelosuppression, hepatotoxicity, pneumonitis. Once weekly; co-prescribe folic acid; never with trimethoprim / co-trimoxazole. |
| Sulfasalazine | FBC, LFT | Myelosuppression (esp. first months), hepatitis, rash. Not significantly immunosuppressive. |
| Hydroxychloroquine | No routine bloods; annual eye review | Long-term retinopathy. Not significantly immunosuppressive. |
| Leflunomide | FBC, LFT, BP, weight | Hepatotoxicity, hypertension, diarrhoea/weight loss. Long half-life – needs cholestyramine washout. |
| Azathioprine | FBC, LFT; check TPMT before starting | Myelosuppression. Never full-dose with allopurinol (life-threatening toxicity). |
| Mycophenolate | FBC, LFT | Myelosuppression, GI upset. Strongly teratogenic (men and women). |
Source: BSR 2025 csDMARD guideline · MHRA
🔒 Sign up free to read the full topic
You're viewing a free preview. Create a free account to unlock the rest.
Sign up free →Sample topics are open to everyone in the Free Sample Bundle.