the use of cotrimoxazole in elderly patients carries an increased risk of severe adverse reactions.
may not be tolerated well in patients with HIV / AIDS
do not use in those with G6PD deficiency as risk of haemolytic anaemia
as with all drugs containing sulfonamides, caution is advisable in patients with porphyria or thyroid dysfunction
'slow acetylators' may be more prone to idiosyncratic reactions to sulfonamides
category C in pregnancy
take especial care with prolonged use:
consider folate supplements if prolonged high-dose use.
possible interference with folate metabolism, regular blood counts are advisable in patients on long-term therapy, especially in those at risk (alcoholics, elderly, rheumatoid arthritis, and malabsorption syndromes)
regular FBE, urine analysis and renal function tests should be performed during long-term therapy
patients with renal impairment a reduced or less frequent dosage is recommended in order to avoid accumulation of trimethoprim in the blood.
high doses of trimethoprim, as used in patients with Pneumocystis carinii pneumonia, induce a progressive but reversible increase of serum potassium concentration in a substantial number of patients.
introduction
cotrimoxazole is a broad spectrum antibiotic consisting of two anti-folate antibiotics - trimethoprim and the sulphonamide, sulfamethoxazole
marketed as Bactrim DS and Septrim DS
it's use has declined substantially over the past 20 years on the belief that the sulphonamide component adds little for most infections whilst causing most of the adverse reactions.