DMARDS Flashcards
indications methotrexate
Rheumatoid arthritis
Malignant disease – used as an anti-metabolite in cancer therapy
Crohn’s disease
dosing methotrexate
Rheumatology: dose range 5-25mg once weekly
Gastroenterology: Starting dose – 25mg once weekly for 16 weeks
Maintenance dose – 15mg once weekly
Always prescribe methotrexate in multiples of the 2.5mg tablet strength
common adverse effects methotrexate
Nausea, diarrhoea
Alopecia
Stomatitis – stop treatment if this occurs, mucositis
important adverse effects methotrexate
Myelosuppression including leucopenia and neutropenia
Hepatotoxicity
Pulmonary fibrosis, interstitial pneumonitis
Pericarditis, pericardial tamponade
contraindications methotrexate
Caution in ulcerative colitis, peptic ulcer disease and ulcerative stomatitis
Avoid in pregnancy and breastfeeding, severe hepatic or renal impairment, blood disorders
(severe anaemia, leucopenia or thrombocytopenia), untreated folate deficiency and history
of alcohol abuse/cirrhosis
Hold methotrexate temporarily if patient is systemically unwell with significant infection
requiring anti-infective intervention
interactions methotrexate
Trimethoprim/co-trimoxazole (risk of pancytopenia, do not co-prescribe)
Clozapine (increased risk of agranulocytosis – avoid concomitant use)
Acitretin (increased plasma methotrexate concentration, increased risk of hepatotoxicity –
avoid concomitant use)
Live vaccines (high risk of infection due to immunosuppressive effect of methotrexate)
PPIs
NSAIDs and methotrexate?
NSAIDs (may reduce methotrexate excretion but unlikely to cause clinically significant
adverse effects, concomitant use common in rheumatic disease)
increased risk of nephrotoxicity
Patients should be advised to avoid taking NSAIDs unless prescribed by their specialist doctor.
Baseline tests methotrexate
Baseline tests should include FBC, U&E, LFT, ESR and CRP.
Selected patients may require
pulmonary function testing and CXR.
Drug monitoring methotrexate
FBC, U&E and LFT should be checked every 1-2 weeks until
patient is stabilised and then every 2-3 months thereafter (monthly in rheumatology). ESR and CRP
should be re-checked avery 3 months.
what should you ask about at every appt regarding methotrexate SE
Also ask about oral ulceration/sore throat, unexplained rash or unusual bruising at every
consultation.
methotrexate and pregnancy, contraception etc.
Explain to female patients that they must not take this medication during pregnancy.
Both men and women should be advised to use reliable contraception throughout treatment and for 3-6 months after stopping methotrexate.
If a patient or their partner does become pregnant while on
methotrexate they should inform their doctor immediately and the medication should be stopped.
safety netting prescribing methotrexate
Advise patients that they should immediately report to their doctor any features of blood disorder
(sore throat, bruising, mouth ulcers), liver toxicity (nausea, vomiting, abdominal discomfort, dark
urine) or respiratory effects e.g. shortness of breath.
what should you co-prescribe with methotrexate?
When starting a patient on methotrexate you should also prescribe folic acid at a dose of 5mg to be
taken once weekly, 1-2 days after the methotrexate dose.
methotrexate and pleural effusion?
Patients with significant pleural effusion should have this drained prior to starting methotrexate
because the drug may accumulate in this fluid and cause myelosuppression on returning to the
circulation.
what drugs are in the class ‘aminosalycylates’
mesalazine
sulfasalazine
olsalazine
balsalazide
MoA aminosalycylates?
Cyclooxygenase enxymes in the colon
Inhibitor
Inhibit mucosal production of arachidonic acid metabolites such as prostaglandins
Indications aminosalycylates?
- sulfasalazine RA
- mesalazine UC
common adverse effects aminosalycylates?
GI upset (diarrhoea, nausea, vomiting, abdominal pain)
Important adverse effects aminosalycylates?
Acute pancreatitis;
Blood disorders including agranulocytosis;
Lupus erythematosus-like syndrome
(sulfasalazine);
Renal dysfunction – interstitial nephritis, nephrotic syndrome not to be used in
moderate or severe renal impairment.
cautions and contraindications of aminosalycylates
Caution in the elderly, pregnancy and breastfeeding, patients with a history of asthma and
those with hepatic or renal impairment (avoid if severe)
Caution with SULFASALAZINE in patients with G6PD deficiency – observe closely for signs of
haemolytic anaemia
Avoid in patients with known salicylate or sulphonamide hypersensitivity
Stop aminosalicylate if it is suspected that the patient has developed a blood dyscrasia
interactions aminosalycylates
Lactulose – co-prescription will reduce 5-ASA efficacy
Azathioprine (increased risk of leucopenia)
Mercaptopurine (increased risk of leucopenia)
Digoxin – absorption of digoxin may be reduced, review dosage requirement after
introductin of aminosalicylate
drug monitoring aminosalycylates
Baseline FBC, LFTs, ESR, CRP should be checked monthly for the first 3 months then 3
monthly thereafter. Re-check blood count immediately if blood dyscrasia suspected. Also check
renal function (U+E) before starting an oral aminosalicylate, at 3 months of treatment and annually
thereafter (more frequently in renal impairment).
what should you ask everyone at every consultation about if on aminosalycylates
Patients should be asked about oral ulceration/sore throat, unexplained rash or unusual bruising at
every consultation.
indications azathioprine
inflammaotry bowel disease
other things autoimmune and RA and rej of prophylaxis in organ transplantation
common adverse effects azathioprine
nausea
important adverse effects azathioprine
Cancer risk – azathioprine increases the risk of lymphoma and skin malignancies
Bone marrow suppression – anaemia, leucopenia, thrombocytopenia
Hypersensitivity reactions including interstitial nephritis – discontinue immediately
Pancreatitis
contraindications of azathioprine
Caution in hepatic and renal impairment
Avoid in patients with known hypersensitivity to mercaptopurine, those with thiopurine
methyltransferase (TPMT) deficiency and in breastfeeding women
interactions azathioprine
Allopurinol (risk of severe myelosuppression – do not co-prescribe)
Warfarin (reduced anticoagulant effect) – may need to increase warfarin dose
Aminosalicylates (bone marrow toxicity – may require increased monitoring
Trimethoprim/co-trimoxazole (risk of blood disorders)
drug monitoring azathioprine
Baseline tests should include FBC, LFT, U&E, ESR and CRP (may also wish to measure
Thiopurine methyltransferase (TPMT)) level prior to starting – at discretion of initiating specialist).
FBC and LFT should be re-checked weekly for the first 8 weeks or until stable, then monthly
thereafter. ESR and CRP should be re-checked every 3 months.
what should you ask about at every consultation - DMARDS
Also ask about oral ulceration/sore throat, unexplained rash or unusual bruising at every
consultation.
patient communication azathioprine
Explain to patients that this medication increases their risk of skin cancer and it is important that
they take appropriate precautions – avoid excessive sun exposure, use high factor sunscreen.
Explain to female patients that if they become pregnant or are planning to become pregnant they
should continue to take their medication as normal but should notify their doctor as soon as
possible. Both men and women should be advised to use reliable contraception throughout
treatment.
Advise patients that they should take this medication with or after food.
when should you hold methotrexate
Hold methotrexate temporarily if patient is systemically unwell with significant infection
requiring anti-infective intervention
