Pharmacology

Question 1

Approach to discussion of a drug

Answer 1

PRICE ADME Presentation/ Pharamceutics Route of Admine Indications Contraindications Effects /Side effects Absoprtion Distribution Metabolism Elimination

Question 2

Define 1/2 life

Answer 2

Time taken for 50% of drug to be elminated from the body T1/2 = 0.693/ k k=rate constant of elmination = clearance/Vd need 4-5 1/2 lives to get to steady state

Question 3

Define pharamcodynamics

Answer 3

The acitions of the drug on the body

Question 4

Define pharmacokinetics

Answer 4

the actions of the body on the drug- involves absorption; distribution; metabolism ; elimination

Question 5

Define volume of distribution

Answer 5

volume of fluid required to contain total amount of drug in the body at the same concentration as in the plasma Drug amount= Vd x concentrationin plasma at any given time

Question 6

Definition of clearance

Answer 6

Notional volume of biological fluid cleared of susbtance per unit time clearance= rate of elimination/ drug concentration (at that time)

Question 7

Different categories of calcium channel blocker

Answer 7

phenylalkylamines: verpamil dihydropyridines: amlodipine/nimodipine benzothiazepines: diltiazem All block L-type Ca channles but have different affinities for these channels in nodal, cardiac, vascular smooth muscle.

Question 8

Drugs that cause Qt prolongation

Answer 8

Antibiotics: azithromcyin; erythromycin; metronidazole Antifungals: fluconazole; Antidepressants: amyitrytiline Anitpsychotics: resiperidone; haloperidol; clozapine; droperidol; Antiarrythmics: amiodareon; sotalol; Antimalarials; chlorquine

Question 9

Features of antiepileptics: phenytoin; leviteracetam; valproate; carbamazpine

Answer 9

Phenytoin (Dilantin): IV or oral(good oral bioavailability); loading dose 1.5 gm; Heptic metabolism; significant interaction; transition to zero order kinetics so small dose changes; can measure plasma levels; IV dose needs to be given over an hour Leviteracetam(Keppra): IV or oral (good oral bioavailability); loading dose: 500- 1000mg; renal excretion of unchanged drug; nil interactions; Iv dose over 10 minutes Valporate (Epilim): IV or oral; mutlipl interactions ; hepatic metabolism; definitiely teratogenic; IV dose over 10 minutes (10mg /kg up to 800 mg); then 1-2 mg/kg/hr up to max of 2.5 g/day Carbamazpine (tegretol): oral; hepatic metaboilsm; significant interactions; risk of leukopenia;

Question 10

Features of propofol infusion syndrome

Answer 10

unexplained lactic acidosis lypemic serum cardiovascular collapse green urine arrythmias renal failure rhabodmyolisis

Question 11

Name alternatives for anticoagulation in RRT in HITs patients. What is there mechanism of action

Answer 11

Citrate- Ca chelator- beware citrate toxicity Argatroban - direct thrombin inhibitor Bivalirudin - direct thrombin inhibitor

Question 12

name the new oral anticoagulants and some of there features

Answer 12

Dabigatran - direct thrombin inhibitor- no monitoring needed, poor bioavailabilty and poor PPB- can be removed by diaylsis. renal excretion of unchanged drug- avoid in renal failure Rivaroxaban - factor Xa inhibitor- no monitoring needed, good bioavailabiltiy and high PPB- not suitable for removal by dialsysis; hepatic metabolism to active metabolites excreted in urine- avoid in renal failure

Question 13

pharmacologic features of keppra

Answer 13

NAME?

Question 14

potential complications of hypertonic saline

Answer 14

phlebitis extravasation hypercholremic acidosis hypernatremia renal failure confusion rebound intracranial hypertension CCF/ Pulmonay oedema central pontine myelinolysis

Question 15

Risk factors for propofol infusion syndrome

Answer 15

high dose infusion of propofol low carbohydrate diet young catecholamine infusion corticosteroid infusion acute neurologic injury

Question 16

What determines volume of distribution

Answer 16

High Vd: low PPB; low ionisation; high lipid solubility; high tissue binding Low Vd: high PPB; high ionisiation; low lipid solubility ; low tissue binding

Question 17

what does 1/2 life determine

Answer 17

duration of action of single dose time taken to get to steady state ideal dosing interval

Question 18

what is malignant hyperthermia? its features and treatment

Answer 18

Autosomal dominant condition whereby lose normal calicum homeostatis and get increase Ca inlfux into skeletal and cardiac muscle triggers: volatile agents and suxamethonium: features: tacycardai, HTN,muscle rigidity, hyperthemia, acidosis treatemnt: ventilate to 100%; dantrolene (inhibitis Ca release from SR) up to 10 mg/kg; Supportive care including preventio nand treatment of acidosis; DIC; acute renal failure; rhabdomyolisis;