Trimethoprim

Question 1

Indications of Trimethoprim

Answer 1

first line for uncomplicated UTI, alternatives: Nitrofurantoin, amoxicillin

Co-trimoxazole (trimethoprim combined with sulfamethaxazole) used for immunocomromised patients to treat pneumonia

Question 2

Mechanism of action of Trimethoprim

Answer 2

Inhibits bacterial folate synthesis –> slowing bacterial growth (bacteriostatic)

Question 3

Side effects of Trimethoprim

Answer 3

Allergy

GI upset (nausuea, vomiting, sore mouth)

Skin rash

Haematological disorders

Hyperkalaemia

Question 4

Warnings of Trimethoprim

Answer 4

never in first trimester of pregnancy (fetal abnormalities)

Neonates

Folate deficiency

renal impairment

HIV –> increased SE

Question 5

Interactions of trimethoprim

Answer 5

Potassium elevating drugs - increases risk of hyperkalaemia

Folate antagonists

phenytoin (increases folate motabolism)