Section B Flashcards
pharmacokinetics
effects of the body on the drug or fate of the drug in the body
pharmacodynamics
effects of the drug on the body
what are the various methods of administering drugs?
enteral, topical, parenteral
list 4 examples of enteral drug administration
oral, nasogastric, gastronomy, buccal/sublingual
list 4 examples of topical drug administration
skin, eyes/ears/nose, inhalation, rectal/vaginal
list 7 examples of parenteral drug administration
intravenous, intramuscular, subcutaneous, intradermal, intrathecal, epidural, intra-articular
bioavailability
the fraction of the drug administered that reaches the systemic circulation
first pass metabolism
orally, some of the drug is metabolized (inactivated) before entering circulation
enzyme induction and its clinical relevance
increase in drug metabolizing enzyme activity caused by a foreign compound (inducer)
- requires prolonged exposure to inducer
- causes accelerated clearance, reduced drug action and increased formation of toxic metabolites
can cause drugs to be less effective due to rapid clearance
enzyme inhibition and its clinical relevance
decrease in enzyme activity caused by a foreign compound
- requires only single dose
- causes impaired clearance and prolonged action
can cause therapeutic levels to rise to toxic levels in drugs with small therapeutic ratios due to prolonged clearance
half-life
time it takes to eliminate half of a drug from the circulation
affinity
attractive forces between the drug and the receptor (causes drug to bind to receptor)
efficacy
ability of the drug when bound to initiate change
potency
measure of the drug at which it is effective
specificity
ability of the receptor to recognize specific chemical configurations
agonists
bind to receptors, cause conformational change, result in a response
antagonists
bind to receptors, don not cause conformational change, no activation, no efficacy, blocks agonists from binding
partial agonists
bind to receptor, but do not elicit maximal response, must occupy a large number of receptors to elicit a response
why are elderly patients more at risk for ADRs? (8)
- multiple illness
- multiple medications
- altered homeostasis
- altered immunity
- altered pharmacokinetics
- altered pharmacodynamics
- sensitivity to sedatives
- compliance problems
why are people with liver disease more at risk for ADRs? (5)
- encephalopathy risk (sedatives/diuretics)
- clotting factor synthesis not normal -> bleeding
- low protein affects drug binding and fluid balance
- metabolism abnormal -> potential for toxicity
- shunting affects bioavailability
why are people with renal disease more at risk for ADRs? (5)
- failure to excrete drugs
- failure to excrete metabolites
- increased sensitivity to drugs
- side-effects are poorly tolerated
- some drugs may be ineffective
what are the main groups of drugs used to treat hypertension?
A - ACE inhibitors & angiotensin receptor blockers (under 55 and not pregnant)
B - beta blockers
C - calcium channel blockers (over 55 or african american)
D - diuretics
what are the mechanisms and side-effects of ACE inhibitors?
they block formation of angiotensin II and inhibit aldosterone release and blocks breakdown of bradykinin
Cough
Angioedema
Proteinuria
Taste changes
Orthostatic hypotension
Pregnancy fetal renal failure
Rash
Increases renin and decreases angiotensin II
Lytes - hyperkalemia due to decreased aldosterone release
-drop in BP
-fatigue
-headache
-liver damage
-renal failure
what are the mechanisms and side-effects of angiotensin receptor blockers?
they bind to the angiotensin receptor and block vasoconstriction
-fatigue
-hyperkalemia
-renal failure
-syncope
what are the mechanisms and side-effects of beta blockers?
they lower cardiac output, heartrate and renin secretion
B1- bradycardia
- conduction
-heart failure
B2 - bronchospasm
- vasoconstriction
what are the indications for beta blockers?
- angina
- tremour
-dysrhymias - hypertension
- myocardial infarction
- thyrotoxicosis
labetalol used for malignant hypertension
Propranolol used for anxiety SYMPTOMS (sweating, shaking, reduce adrenaline, lower HR)
what are the mechanisms and indications for calcium channel blockers?
they lower calcium available to contractile proteins, lower BP, lower cardiac contractility, lower vascular smooth muscle
- angina (prevention)
- dysrhythmias
- hypertension
what are the side-effects of calcium channel blockers? (dihydropyridine and non-dihydropyridine)
dihydropyridine: hypertension
- headache
- oedema
- flushing
non-dihydropyridine: not first course treatment for hypertension -> used for arrythmias
- bradycardia
- heart failure
what are the mechanisms and side-effects (8) of diuretics?
they inhibit sodium transport in the distal tubule and have a vasodilator effect
e.g thiazide like drugs such as xipamide
- hypercalcemia
- hyperglycemia
- hyperuricemia
- hypochloremia
- hypokalemia
- hypomagnesemia
- hyponatremia
- blood disorders
what do loop diuretics do? give an example and what are the side-effects?
inhibit sodium and potassium transport in the loop of Henley, side-effects same as diuretics e.g. furosemide
what do potassium sparing diuretics do? give an example and side-effects
increase excretion of sodium, water, chloride and calcium
decrease excretion of potassium and hydrogen ions
side- effects - ▪ dizziness, orthostatic hypotension
▪ dry mouth
▪ nausea, vomiting, diarrhea
e.g. amiloride
what drugs are used to treat myocardial infarction?
anti-coagulants, A, B and C drugs
name 2 anti-coagulants
warfarin and heparin
warfarin
decreases the biological activity of clotting factors II, VII, IX, and X and anticoagulant proteins C and S
teratogen, vitamin K antagonist, warfarin metabolism affected by several drugs and food, monitored using INR - 2.5
heparin
binds to antithrombin III which catalysts inactivation of factors IIa, Xa, IXa and XIIa
monitored using aPTT
what are the side-effects of heparin? (4)
- alopecia
- hyperkalemia
- hemorrhage/thrombocytopenia
- osteoporosis
name an anti-platelet drug
aspirin
aspirin
inhibits cyclooxygenase, preventing formation of thromboxane A2
what are the indications for aspirin?
- acute coronary syndrome
- acute stroke
- prevention of cardiovascular disease
- alternative to anti-coagulants in A.Fib
what are the main drug groups used in treating asthma?
bronchodilators (relievers) and anti-inflammatory (controllers)
give 3 examples of bronchodilators
B2 agonists, antimuscarinics and methylxanthines
give 3 examples of anti-inflammatories
corticosteroids, lukasts and chromones
what drugs are used to treat anaphylaxis and what do they do?
adrenaline - inhibits mast cell release of mediators
corticosteroids - reduce inflammation
what do NSAIDs do?
they inhibit COX1 and COX2 which decreases prostaglandin synthesis
- anti-inflammatory
- analgesic
- anti-pyretic
- antiplatelet
- anti-tumour
what are the side-effects of NSAIDs? (9)
headaches
dizziness
stomach pain
bone marrow toxicity
GI issues
hypersensitivity
liver damage
renal impairment
vascular disease
what are the side-effects of opioids?
tolerance, dependance and withdrawal
what are the consequences of alcohol use?
- depressant -> causes disinhibition and dependence
neuro: depression, stroke, neuropathy
cardio: cardiomyopathy, hypertension
resp: TB, pneumonia
gastro: gastritis, ulcers, liver disease, pancreatitis - infertility, osteoporosis, cancers
what are the consequences of cocaine use? (11)
- psychosis
- seizures
- dysphoria
- mydriasis
- stroke
- hyperthermia
- tachycardia
- heart attack
- hypertension
- kidney failure
- blood coagulation
what are the consequences of cannabis use?
- impaired short-term memory
- impaired motor coordination
- altered judgement
- paranoia/psychosis
- addiction
- altered brain development
- cognitive impairment
- diminished life satisfaction
- risk of chronic psychosis disorders
what are the principal drugs used in treating peptic ulcers?
- antacids: neutralize acid and pepsin
- alginates: prevents reflux
- H2 receptor antagonists: reduce acid release
- chelates: coats ulcer
- proton pump inhibitors: reduce acid release and pepsin activation
what are the principal drugs used in treating constipation?
- bulk: increase fecal mass, promotes peristalsis (methylcellulose)
- osmotic: increases water in large bowel (lactulose)
- stimulants: increase intestinal motility (senna)
- stool softeners: emollients (glycerol)
what are the uses and action of nitrates?
- used to treat angina and heart failure
- relaxation of smooth muscle of veins and arterioles
causes reduction in venous return (preload) which reduces left ventricular work. Arterioles also relax (afterload) rapid symptomatic relief of angina.
what are the side effects of nitrates?
flushing, headache and postural hypotension
