Definitions Flashcards
Clearance
Volume of plasma cleared of a drug per unit time
Half life
Time taken for drug concentration to halve - dependent on volume of distribution and clearance
Volume of distribution
Volume into which drug distributes
What type of drugs have high volume of distribution?
Lipid soluble
What types of drugs have low volume of distribution?
Water soluble
First order kinetics
Clearance of drug is proportional to concentration
Zero order kinetics
Clearance of drug is NOT necessarily proportional to concentration
Name three drugs which follow zero order kinetics
Ethanol
Salicylate (aspirin)
Phenytoin
Bioavailability
% of the dose which reaches systemic circulation
Which mechanism of drug delivery has 100% bioavailability?
IV
Multiple dosing
The principle of giving drugs at intervals allowing the concentration to reach a steady state
In how many half lives will most multiple dosing drugs reach steady state?
5
Loading dose
A larger initial dose used to decrease the time needed to reach steady state
Name some drugs where multiple dosing strategies are employed
Phenytoin
Digoxin
Amiodarone
Theophylline
First pass metabolism - definition and location
Metabolism and inactivation of a drug before it reaches systemic circulation
Common in gut wall and liver
Name some drugs which experience first pass metabolism
Propranolol
Morphine
Nitrates
List the 3 pathways of drug metabolism and elimination
Excretion of unchanged drug
Phase 1 metabolism and renal excretion
Phase 2 metabolism and renal excretion
Phase 1 metabolism
Creation of reactive functional groups
List some methods of phase 1 metabolism
Oxidation - P450 system
Reduction
Hydrolysis
Phase 2 metabolism
Production of polar compounds
What kinds of reaction occur in phase 2 metabolism?
Conjugation reactions
What are the 2 most common P450 enzymes?
CYP 3A4
CYP 2D6
What are the conditions of the CURB-65 mnemonic and what is it used for?
Use - determine severity and treatment of CAP: a score >2 requires admission and Rx with IV abx
C = confusion: AMTS < 8/10 U = urea > 7.5 mmol/L R = resp rate > 30 B = BP systolic < 90 mmHg 65 = age > 65
What are the 4 main principles of pharmacokinetics
Absorption
Distribution
Metabolism
Excretion
Define the following types of drug allergies
(1) Type 1
(2) Type 2
(3) Type 3
(4) Type 4
Type 1 - anaphylaxis
Type 2 - cytotoxic antibodies
Type 3 - immune complexes
Type 4 - cell-mediated
List some drugs that can cause neutropenia
Carbamazapine
Carbimazole
Clozapine
Sulfasalazine
Name a class of drug that is likely to produce cholinergic side effects
Anti-cholinesterases
List some cholinergic side effects
Salivation Bronchoconstriction Lacrimation Urination Diarrhoea Emesis Miosis - pupillary constriction Sweating
Name some drugs likely to produce anti-muscarinic/cholinergic side effects
Anti-muscarinics… ipratropium, anti-histamines, TCAs, antipsychotics, atropine
list some anti-muscarinic/cholinergic side effects
Constipation Urinary retention Mydriasis - pupillary dilation Blurred vision Bronchodilation Drowsiness Dry skin / eyes
List some P450 enzyme inducers (HINT: think PC BRAGS)
Phenytoin
Carbamazepine
Barbiturates Rifampicin Alcohol (chronic use) Griseofulvin St. John's Wart
List some P450 enzyme inhibitors (HINT: think AO DEVICES)
Allopurinol
Omeprazole
Disulfiram Erythromycin Valproate Isoniazid Ciprofloxacin Ethanol (acute intoxication) Sulphonamides
List some drugs you should stop before surgery (HINT: think I LACK OP)
Insulin
Lithium
Anticoagulants
COCP
K-sparing diuretics
Oral hypoglycaemics
Perindopril (i.e. ACEi)
List the drugs that require monitoring
guys with large dongles make totally perfect internet connections
Gentamycin / Vancomycin Warfarin Lithium Digoxin Methotrexate Theophylline Phenytoin Insulin Ciclosporin
List some drugs (apart from enzyme inhibitors) that augment the actions of warfarin
Alcohol
Statin
NSAIDs
Amiodarone
List some drugs that are affected by renal impairment
Digoxin
Gentamicin
Atenolol
Amoxicillin
List some nephrotoxic drugs
Gentamicin - ototoxic and nephrotoxic (tubular damage)
Lithium - nephrogenic DI and tubular damage
Ciclosporin - decreases GFR and tubular damage
ACEi - decreases GFR
ARB - decreases GFR
NSAIDs - decreases GFR and papillary necrosis
List some hepatotoxic drugs and the effects they have
Cholestatic damage - flucloxacilli, erythromycin, OCP, TCA
Hepatocellular damage - paracetemol, anti-epileptics (eg: valproate), anti-TB (eg: rifampicin), methotrexate, statins
Chronic hepatitis - methyldopa
Gallstones - COCP
