Sulfasalazine therapy

Sulfasalazine or Salazopyrin is indicated for the treatment of active Rheumatoid Arthritis and some other inflammatory arthropathies. It is normally used together with Non Steroidal Anti-inflammatory Drugs particularly in the early stages of treatment. Response to treatment cannot be expected before three months and may not occur until after six months of treatment.

CONTRA-INDICATIONS

Pregnancy and lactation
Gross renal, lung, bowel or hepatic disease
Blood dyscrasias
Known hypersensitivity to sulphonamides
Reversible male sub-fertility

DOSAGE

Starting Dose 500mg daily
Dose Increments 500mg weekly until dose of 1g twice a day.
If inadequate response dose can be increased to 3g daily in divided doses.
Total duration of treatment - as long as indicated by clinical condition.
Use enteric coated preparation.

MONITORING

Pre-treatment screening
monitoring every 4 weeks for 3 months
then every 3 months.

PRE TREATMENT SCREENING	EACH MONITORING VISIT
Haemoglobin Total white cell count Neutrophil count Platelet count Biochemical Profile	Haemoglobin Total white cell count Neutrophil count Platelet count Liver function tests

ADVERSE EVENTS

LABORATORY EVENTS	VALUES	ACTION
Leucopaenia	< 3.5 x 10 ⁹ /l	STOP + seek advice
Neutropaenia	< 2.5 x 10 ⁹ /l	STOP + seek advice
Thrombocytopaenia	< 150 x 10 ⁹ /l	STOP + seek advice
Macrocytosis	> 100	Check B12 and folate
Sequential falls in WBC or neutrophils	> 10% on 3 occasions	STOP + seek advice
Sequential falls in Platelets	> 10% on 3 occasions	STOP unless falls are from high level e.g. 600, 500, 400 x 10 ³ which are response to treatment
Elevation of liver enzymes (AST, ALT)	> 3x normal	STOP drug Repeat LFTs Mild transaminitis is common and normally settles.

CLINICAL ADVERSE EVENTS	MANAGEMENT
Rash	Often non-specific erythematous, dry and itchy. STOP drug if severe Consider using 1% hydrocortisone and/or anti-histamines. Consider other causes of rash. If mild re-introduce drug when settled.
Mouth Ulcers/Stomatitis	STOP if severe. Reduce dose if mild/moderate. Consider carbenoxalone or Difflam mouth washes. Consider other causes.
Fever/Flu like illness	STOP drug Unusual hypersensitivity reaction Do not re-introduce
Nausea	Reduce dose Take with food, try anti-emetic. STOP if unacceptable
Urine discolouration	Reassure
Discolouration of soft contact lenses	Warn patient

Source: Dr PR Crook, Consultant Rheumatologist.