Pharmacology

Question 1

Inducers

Answer 1

Erythromycin**
Ciprofloxacin
Fluconazole
Isoniazid
Metronidazole
Grapefruit juice
Valproate
Bactrim

Question 2

Inhibitors

Answer 2

Carbamazapine
Rifampicin
Alcohol
Phenytoin
Phenobarbitone**
Steroids
OCP

Question 3

Steroids (potency)

Answer 3

Betamethazone 0.75
Dexamethasone 0.75
Methylprednisolone 4
Prednisolone 5
Hydrocortisone 20
Cortisone 25

Question 4

Biologics/monoclonal antibodies

Answer 4

Do Quantiferon Gold to check for TB prior to starting

Infliximab - TNF alpha inhibitors (SE: TB, Hep B, fungal)
Rituximab - CD20 B/T lymphocyte inhibitor
Anakinra - IL1 antagonist (SE: pneumonia)
Tocilizumab - IL6 antagonist (SE: TB)
Omalizumab - IgE (inhibits IgE binding)
Eculizumab - anti c5
Etanercept - TNF blocker

Question 5

Formulas

Answer 5

Time to steady state is 5 hours

Concentration = dose / volume

Clearance = dose / AUC

VD = dose / concentration

How many compartments = how many gradients

Loading dose = VD x target plasma concentration

Bioequivalence: compare 2 drugs, +/- 20% so, CI of AUC 0.8 - 1.25 (80%-125%)

Clockwise hysteresis loop (acute tolerance e.g. adrenaline)
Anticlockwise hysteresis loop (delayed distribution e.g. digoxin, warfarin)

EC50 = potency Emax = efficacy

Competitive agonist - shifts curve to RIGHT (same curve)
Partial agonist - blunts curve (reduced efficiency)
Irreversible/non-competitive antagonist - blunts curve +/- shifts to right (Reduces efficacy +/- reduces potency)
Reversible/competitive antagonist - shifts curve to the right (less potent, same efficacy)