sulfonamides

Question 1

what does co-trimoxazole contain

Answer 1

sulfamethoxazole and trimethoprim

Question 2

why does co-trimaxazole contain sulfamethoxazole and trithoprim to be used in combination

Answer 2

synergistic activity (aka act together)
importance of sulfonamides has decreased due to increased AMR and their replacement by abx that are generally more active and less toxic

Question 3

dose of co-trimoxazole for moderate-severe diabetic foot infection

Answer 3

960mg BD for min 7 days up to 6 weeks for osteomyelitis

Question 4

frequency of dosing for co-trimox

Answer 4

BD

Question 5

common SE co-trimox

Answer 5

Diarrhoea; electrolyte imbalance; fungal overgrowth; headache; nausea; skin reactions

Question 6

co-trimox is associated with rare but serious SE. discontinue immiediately if …

Answer 6

blood disorders: leucopenia, thrombocytopenia, megaloblastic anaemia, oesionphilia, haemophagocytic lymphahistiocytosis

skin reactions/rash - SJS etc

Question 7

what is this and what to do if it develops

Answer 7

A&E needs immediate treatment in hospital

SJS - severe . stop taking.

Question 8

signs of SJS

Answer 8

can start with flu-like symptom
circular rash appears after a few days on upper body and quickly spreads to limbs, face etc usually not itchy
rash is darker on inside, lighter around edges
they then blister
skin peels v easily
can get blisters on lips, mouth, throat - difficulty swallowing
can get blisters on eyes - eye pain, sight problems, photophobia
can get blisters on tube that you pee through - making peeing painful

Question 9

monitoring

Answer 9

Monitor serum potassium and sodium in patients at risk of hyperkalaemia or hyponatraemia.

Monitor blood counts on prolonged treatment.

Question 10

sulfadiazine - what is its only indication

Answer 10

prevention of rheumatic fever recurrence

Question 11

sulfadiazine interacts with vit k antagonists

Answer 11

increases ac effect

Question 12

sulfadiazine interacts with this high risk antipsychotic

Answer 12

Sulfadiazine might increases the risk of neutropenia when given with Clozapine. Manufacturer advises avoid.

Question 13

avoid this urinary antiseptic agent with sulfadiazine

Answer 13

Methenamine might increase the risk of crystalluria when given with Sulfadiazine. Manufacturer advises avoid.

Question 14

interaction with MTX & sulfadiazine

Answer 14

Sulfadiazine is predicted to increase the exposure to Methotrexate. Manufacturer advises use with caution or avoid.