Week 10: Sulfonamides, Trimethoprim, and Nitrofurantoin

Question 1

Sulfonamides/Trimethoprim MOA

Answer 1

Sul”f”onamides block “f”olic acid synthesis
Trimethoprim inhibits DNA synthesis

work synergistically to cover more and CIDAL

Question 2

Sulfamethoxazole and Trimethoprim (Bactrim) Indications

Answer 2

• UTI (1st line)
• MRSA (2nd line)
• PCP pneumonia
• post transplant prophylactic

Question 3

Sulfonamides and Trimethoprim cautions/CIs

Answer 3

• Sulfa allergy
• G6PD
• No pregnancy
• Avoid in pediatrics < 2 months old

Question 4

Sulfonamides/Trimethoprim ADRs

Answer 4

• agranulocytosis (STOP MED!)
• crystalluria & kernicterus (bilirubin)= nephrotoxicity = hydrate up!!
• hemolytic anemia
• photosensitivity
• hyperkalemia
• steven johnson syndrome
• H/A, dizziness

Question 5

Nitrofurantoin MOA/Indications

Answer 5

• interferes with bacterial protein synthesis, cell wall synthesis, and aerobic energy metabolism
• concentrated in kidneys

Indic: UNcomplicated UTI (1st line)

Question 6

Nitrofurantoin ADRs

Answer 6

• urine discoloration (orange/brown color)
• hemolytic anemia
• peripheral neuropathy

Question 7

Nitrofurantoin cautions/CIs

Answer 7

• avoid if CrCl < 30mL/min
• caution if CrcL < 60 mL/min
• avoid in G6PD
• AVOID in late pregnancy (38-42wks) and lactation when infant is < 1 month old
• NO in infants < 1 mo old (risk of neonatal hemolytic anemia)