Dosage Regimens

Question 1

Describe PK-PD integration.

Answer 1

-studies that consider best approach prior to clinical trial
>better than titration studies (look only at PD)
-drug therapy = achieve max benefit w min risk of toxic effect
>reach steady state (PK)
—(+/-) loading dose if need to achieve earlier
>to get therapeutic effect (PD)

Question 2

Describe intermittent dosing.

Answer 2

-wide therapeutic window considering PK
>owner compliance
>(+/-) practicability in hospital
-if short t1/2 = clinical efficacy prolonged between administration
-long t1/2

Question 3

Describe constant rate infusion.

Answer 3

-avoid peak & through, include:
>narrow therapeutic window
>short t1/2 = short efficacy
—intermittent dosing not an option for practical reason for max efficacy
(Drugs w long t1/2 can benefit from CRI)

Question 4

Describe the different types of drugs.

Answer 4

1. Analgesics
   -opioid: morphine, fentanyl
   -NMDA antagonist: ketamine
   -Na channel blockers: lidocaine
   -a2 agonists: dexmedetomidine
2. Anaesthetics
   -GABA agonists: propofol
3. Anticonvulsants
   -GABA agonist: phenobarbital, diazepam, midazolam
4. Cardiovascular drugs
   -sympathomimetics: dopamine, dobutamine, epi
   -Na channel blocker: procainamide
   -Ca channel blocker: diltiazem
   -nitroprusside
5. Diuretics: mannitol, furosemide
6. Glu regulator: insulin, glucagon
7. Time dependent antibacterial antimicrobials

Question 5

Describe loading dose.

Answer 5

-relationship between Vd, D, Cp
(D is bioavailability)

Question 6

Describe a maintenance dose.

Answer 6

-relationship between dosing rate, CLB, Cp(ss)
-dosing rate = CLB, Vd, t1/2