Trimethoprim

Question 1

What is it indicated?

Answer 1

UTI in men and non-pregnant women

Prevention recurrent UTI

Acne vulgaris

Prostatitis

treatment and prevention of pneumocystis pneumonia in immune suppression, e.g. HIV infection.

Question 2

What is the spectrum of activity of this drug?

Answer 2

Broad activity against many gram-positive and negative bacteria but this is increasingly limited by resistance

Combination with a sulfonamide (e.g. sulfamethoxazole, as co-trimoxazole) extends the spectrum to include activity against the fungus

Question 3

How does it work?

Answer 3

Trimethoprim inhibits bacterial folate synthesis, slowing bacterial growth

Question 4

What side effects occur with these drugs?

Answer 4

GI upset and skin rash
Changes the colour of urine to dark yellow or brownish colour
Severe hypersensitivity
Megaloblastic anaemia
Leukopenia
Thrombocytopenia
Hyperkalaemia and elevated of plasma creatinine concentration

Question 5

What warnings occur with these drugs?

Answer 5

Contraindicated in the first trimester pregnancy
Folate deficiency
Renal impairment
Neonate and older people and individuals with HIV infection are more susceptible to adverse effects