General principles Flashcards
1
Q
Vd
A
amt of drug in body / plasma drug concentration
2
Q
T 1/2
A
0.7 *Vd / Clearance
3
Q
Clearance
A
rate of elimination of drug / plasma drug concentration
4
Q
Loading dose
A
Cp x Vd / F where Cp = target plasma concentration and F = bioavailability
5
Q
Maintenance dose
A
Cp * Cl * Tau / F, where Tau = dosage interval and Cp = target plasma concentration.
6
Q
zero order elimination drugs
A
Phenytoin, Ethanol, Aspirin
7
Q
weak acid drugs
A
phenobarbital, methotrexate, aspirin. treat overdose with bicarb. trapped in basic environments.
8
Q
weak base drugs
A
amphetamines. trapped in acid environments. treat overdose with ammonium chloride.
9
Q
Therapeutic index
A
Td 50 / Ed 50. Td 50 = median toxic dose. Ed 50 = median effective dose. TITE.
Higher TI value, safer drug.
