TABLE 2.

Prophylactic regimens for PCP^a

Drug name	Dose	Notes	Adverse drug events and side effects
Trimethoprim sulfamethoxazole	One single- or double-strength tab po daily or one double-strength tab po three times a week	Drug-drug interactions with ACEi/ARB/spironolactone Doubles as prophylaxis against other pathogens (e.g., toxoplasma) and several bacterial infections (respiratory, enteric, and urinary pathogens); if used for this dual purpose, 1 DS tab daily may be considered. When selecting the regimen, balance toxicity vs efficacy.	Rash (including Stevens-Johnson syndrome), hyperkalemia, increased creatinine, transaminase elevation, neutropenia, and thrombocytopenia
Atovaquone	1,500 mg po daily	Should be taken with a fatty meal to increase absorption Can be expensive and has an unpleasant taste	Gastrointestinal upset, diarrhea, fever, transaminase elevation, and rash
Dapsone	100 mg po daily (if toxoplasma serology is negative) Up to 200 mg daily combined with pyrimethamine and folinic acid (if toxoplasma serology is positive)	Option to combine with pyrimethamine for cross-protection against toxoplasmosis Screen for G6PD deficiency prior to use.	Rash, fever, nausea/vomiting, hemolytic anemia, methemoglobinemia, and transaminase elevation
Aerosolized pentamidine	300 mg monthly via nebulizer Biweekly dosing has also been studied	Requires specialized personnel and equipment Potential to transmit respiratory pathogens Risk of isolated apical disease or extrapulmonary disease	Bronchospasm and cough

^a 1823 G6PD, glucose-6-phosphate dehydrogenase; ACEi, acetylcholinesterase inhibitor; ARB, angiotensin receptor blocker; DS, double strength; po, per os.