Pharmacology - Pharmacology and Patient Safety Flashcards
Sources of info for dug hx
From patient or relatives From medical notes From clinic letter/ discharge summaries From computer print-out or shard care record Checking the bottle/ packets Nursing home drug charts
Drugs w/ high risk of error
Insulin and warfarin
Bivaribale doses w/ daily adjustment and its individualised (no find dose)
Cross-checking drugs
Check interactions w/ other drugs
Match against hx of allergy, or poor response to similar drugs
Suitability to individual – risk factors for adverse reaction, renal/ liver disease
Steps to choosing a drug
Identify classes of drugs
Compare the groups
Select formulation and trearment duration
Comparing groups of drugs
How they work, what level of efficacy
Safety – adverse effects, interactions
Suitability/ convenience – tablets/ injections, once daily etc
Cost
Avoiding harm
Lowest effective dose, shorter period
Deliver drug directly to site (skin creams, asthma inhalers)
Reduce risk – e.g. give bone protection if pt is on corticosteroids that cause osteoporosis
Consider non-drug options
Drugs that. may cause a haemorrhage if used together
Aspirin – knocks out platelets
Corticosteroid – thins the stomach lining
NSAIDs – dissolves stomach lining
Therapeutic effects of NSAIDs
Anti-infl
Analgesic
Antipyretic
Anti-infl effects of NSAIDs
Decreases PGE2 and PG1E (COX -1,2,3 inhibitors)
Prostacyclin
PGI2
Analgesic effects of NSAIDs
Decreased prostaglandins makes nerves less sensitive to infl mediators (bradykinin, 5-HT)
Antipyretic effects of NSAIDs
Decreased IL-1
Imprecise targets of NSAIDs
Block COX enzymes –> reduces (too many) PG
Useful/ friendly PG blocked
What happens when useful PG are blocked
Stomach – acid gets through, ulcer occurs
Platelet activity – less clotting, more bleeds
How do NSAIDs damage the stomach
Direct erosion of gastric lining
Indirect – block prostaglandins – unable to make protective mucus barrier against acid
Off target problems w/ NSAIDs
Kidney failure
Heart failure
Toxicity of corticosteroids
Little GI toxicity on their own
High risk together w/ NSAIDs
Drugs given for Gout
NSAIDs, colchicine for acute flare-ups
Allopurinol for chronic prevention
Drugs gives for osteoporosis
Bisphosphonates
Denosumab
Efficacy of NSAIDs for Gout
Moderate to good
Safety of NSAIDs for Gout
Short-term OK, but can cause GI bleed, renal failure, heart failure if high dose or longer-term
Suitability of NSAIDs for Gout
Inexpensive, easy to take, but contraindication in GI or cardiac disease
Dose of NSAIDs for Gout
Ibuprofen 400-800 mg tds
Naproxen 750 mg stat, then 250 mg tds for 7 days
Colchicine mechanism
Decreases infl by inhibition of granulocyte migration and inhibition of lymphocyte migration and division
Depolarisation of microtubules
Efficacy of colchicine for Gout
V good
Safety of colchicine for Gout
Nausea and diarrhoea very common
Bone marrow suppression and renal failure over longer term
Suitability of colchicine for Gout
Good option if cannot take NSAIDs; similar efficacy to naproxen but 2x greater diarrhoea
Colchicine prescription
Colchicine 0.5mg tds for 3-4 tds
Stop if diarrhoea/ vomiting
Shouldn’t exceed total 6mg in one course
Low dose can be used longer period e.g. colchicine 0.5mg daily for a few weeks to stop recurrent flares
Other uses of colchicine
Pericarditis (infl of lining of the heart)
Bechet’s disease (urogenital ulcers, arthritis)
Reduce infl after heart attack
Corticosteroids in gout
Anti-infl
Local injection if only single joint affected e.g. wrist
Systemic (tablets) i.e. oral prednisolone if severe
Efficacy of corticosteroids for Gout
Good
Safety of corticosteroids for Gout
Short-term is generally ok
Suitability of corticosteroids for Gout
Those who cannot have NSAIDs or colchicine (e.g. older patients w/ multiple co-morbidities)
Canakinumab
Selective inhibitor of IL-1 receptor
Subcutaneous injection, can last up to 12 weeks
For patients affected by frequent, severe acute gout that isn’t relieved by other drugs