DR Medhat MRCP

- Ideal (lean) body weight (not total body weight) should be considered when calculating
digoxin dose otherwise overestimating the distribution space in obese patient will →
digoxin toxicity So ,digoxin toxicity in an obese patient is most likely due to ↓ volume of
سؤال distribution.
Drug metabolism :
- The metabolism of the drugs is classified according to :
A. Site of metabolism (which depends on mode of administration)
General metabolism ( I.V, I.M , S.L ,Inhalation drugs→ to systemic circulation)
i.e the drug does its effect 1 st then metabolized
First pass metabolism (i.e metabolism of the PO drugs before they reach
systemic circulation i.e reaching the liver through
enterohepatic circulation) e.g ASA ,nitrates ,verapamil
سؤال ,propranolol, lignocaine
B. Phases (types) of biochemical reactions:
Phase I reactions (oxidation ,reduction ,hydrolysis)
Phase II reactions (conjugation to glucoronate ,acetate ,sulphate)
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