Dapsone Flashcards
Q6.
Features of the dapsone hypersensitivity syndrome (sulphone syndrome) include:
a.
A maculopapular eruption
b.
Hepatocellular hepatitis
c.
Lymphopaenia
d.
Agranulocytosis
e.
Reticulocytosis
T T F F F
T/F
Dapsone is lipid soluble and water insoluble
True
t/F
Dapsone is well absorbed from the gut, with 70-80% of single oral dose absorbed
True
70-80% of single oral dose absorbed
T/F
Sulfoxone is the parent drug of dapsone
False
Dapsone is parent drug of Sulfoxone
How is dapsone metabolized?
Two ways
N-acetylation
N-hydroxylation
How is dapsone excreted ?
Conjugated in liver as dapsone glucoronide
- more water soluble
- rapidly excreted by kidneys
Treatment with probenecid decreases renal clearance
When treatment with dapsone is prolonged a peripheral motor neuropathy has been described eg. Hand wasting
T
Dapsone half life
24-36 hours
Dapsone with treatment with probenecid decreases renal clearance
T
Dapsone is conjugated in liver as dapsone glucoronide
T
Dapsone is not inhibited by use of cimetidine
False
Anti emetics decrease serum levels of dapsone
False
Increase
Drugs that Increase haematologic risk of dapsone
Sulfonamides DHFR inhibitors (MTX, trimethoprim)
Cimetidine 1200-1600 daily has been shown to reduce methaemoglobinaemia levels and symptoms in chronic dapsone Rx
T
Methylene blue should not be given in g6pd def as causes haemolytic anaemia
T
