OPRA: Pharmacokinetics & pharmacodynamics
PK/PD is about ~10% of OPRA — and it overlaps heavily with the calculations that trip people up, so it's worth nailing.
High-yield areas
- ADME and what each step sets (dose, interval, loading dose)
- Half-life, clearance, volume of distribution and steady state
- Loading vs maintenance dose calculations
- Potency vs efficacy and the therapeutic index
How to study it
Treat PK/PD and calculations together — practise the formulas on randomised values in the free Calculations Lab until the method is automatic.
Practise PK calculations free
Drill half-life, loading-dose and clearance problems in the free Calculations Lab.
Start freeFrequently asked questions
How much of OPRA is pharmacokinetics?
Pharmacokinetics and pharmacodynamics is approximately 10% of the exam.
What does the PK/PD domain cover?
ADME principles, half-life, volume of distribution, clearance and steady state, dose individualisation in renal and hepatic impairment, therapeutic drug monitoring, and dose-response relationships.
Are there calculations in this domain?
Yes. Expect applied numeracy such as loading and maintenance doses, creatinine clearance, and adjusting a dose from a steady-state drug level.