Bactrim (Co-trimoxazole)
Sulfamethoxazole and
trimethoprim
The importance of the
sulphonamides has decreased as a result of
increasing bacterial resistance and their
replacement by antibacterials which are
generally more active and less toxic.
Sulfamethoxazole
(sulphamethoxazole) and trimethoprim are used
in combination because of their synergistic
activity. However, co-trimoxazole is
associated with rare but serious side-effects
(e.g. Stevens-Johnson syndrome and blood
dyscrasias, notably bone-marrow depression
and agranulocytosis) especially in the
elderly (see CSM recommendations below).
| CSM
recommendations.
Co-trimoxazole should be limited to
the role of drug of choice in Pneumocystis
carinii pneumonia; it is also
indicated for toxoplasmosis
and nocardosis. It should now
only be considered for use in acute
exacerbations of chronic
bronchitis and infections of
the urinary tract when there is
good bacteriological evidence of
sensitivity to co-trimoxazole and
good reason to prefer this
combination to a single
antibacterial; similarly it should
only be used in acute otitis
media in children when there is
good reason to prefer it. |
Trimethoprim can be
used alone for urinary- and respiratory-tract
infections and for prostatitis, shigellosis,
and invasive salmonella infections.
Trimethoprim has side-effects similar to
co-trimoxazole, but they are less severe and
occur less frequently.
British National Formulary,
published by the British Medical association
and the Royal Pharmaceutical Society of Great
Britain. March 2003.