antibioticsbooks

134 PART 2 Antibacterial Drugs
Spectrum
Good: Staphylococcus aureus (including many
MRSA strains), Haemophilus influenzae, Stenotrophomonas
maltophilia, Listeria, Pneumocystis
jirovecii (formerly known as P. carinii), Toxoplasma
gondii (pyrimethamine and sulfadiazine)
Moderate: enteric GNRs, S. pneumoniae, Salmonella,
Shigella, Nocardia
Poor: Pseudomonas, enterococci, S. pyogenes,
anaerobes
Adverse Effects
Dermatologic: TMP/SMX frequently causes rash,
usually because of the sulfamethoxazole component.
Rash is much more common in HIV/
AIDS patients. Although these rashes are usually
not severe, life-threatening dermatologic
reactions such as toxic epidermal necrolysis
and Stevens-Johnson syndrome have been
documented.
Hematologic: A primarily dose-dependent bonemarrow
suppression can be seen with TMP/
SMX, especially at the higher doses used to
treat Pneumocystis infections.
Renal: Confusingly, TMP/SMX can cause both true
and pseudo-renal failure. Crystalluria and AIN
caused by the SMX component can lead to acute
renal failure; however, the blockade of creatinine
secretion by TMP can cause an increase
in serum creatinine without a true decline
in glomerular filtration rate. TMP can also
cause hyperkalemia in a fashion similar to the
potassium-sparing diuretics (e.g., triamterene).