2. Sulfonamides

Question 1

Examples of sulphonamides

Answer 1

co-trimaxole

Trimethoprim / Sulfamethoxazole

Question 2

Co-trimaxole composition

Answer 2

Sulfamethoxazole and trimethoprim

Question 3

Trimethoprim spectrum of activity

Answer 3

narrow-spectrum

Question 4

Trimethoprim mechanism of action

Answer 4

Prevents DNA synthesis so is bactericidal

Question 5

Trimethoprim dose

Answer 5

200mg BD or at a lower dose of 100mg at night to prevent recurrent infections

Question 6

Trimethoprim side effects

Answer 6

Blood disorders (as trimethoprim is an anti-folate, to block actions of folic acid. Folic acid is needed to make DNA and thus new cells, which impacts the making of new blood cells such as red and white blood cells.)

Patients must report signs and symptoms of an infection such as a fever, sore throat or mouth ulcer or bleeding/bruising.

Trimethoprim can also cause hyperkalamia.

Question 7

Sulphonamides typically treat

Answer 7

Pneumonia, respiratory tract infections, shigellosis, urinary-tract infections

Question 8

Appropriateness of sulphonamides in pregnancy

Answer 8

Teratogenic in the first semester. If it is used in pregnancy, a high dose of folic acid (5mg) should be given for the duration of the course.

Only reserved for pneumocystitis jirovecci pneumonia

Question 9

Apropriateness of dyaminpyridimines in pregnancy

Answer 9

Trimethoprim or co-trimaxole are unsuitable in pregnancy