Adverse drug reactions and interactions Flashcards
Adverse drug reactions, 2 types?
Augmented
Bizarre
Type a adr?
Exaggeration of intended therapeutic effect e.g.
- hypotension with antihypertesinves
- dehydration with diuretics
Unrelated to intended therapeutic effect e.g.
- hyponatraemia with thiazides
- brethlessness with. Beta blockers
Increased risk of type A ADR?
Drug concentrations - higher dose
Patient factors
Management of the A ADR?
Reduce dose
Try alternative
Keep on if necessary and treat the ADR
What are high risk clinical scenarios for augmented ADRs?
Liver impairment
Heart failures
Elderly/frail
Dehydration
Renal impairment
What drugs make to at high risk of ADR when pt has heart failure?
Nsaids
Glitazones
What drugs make out at high risk of ADR if pt has renal impairment?
Nsaids
ACE/ARBS
Metaformin
LMWH
Digoxin
Antibiotics
Opiates
What drugs make you at higher risk of ADR if ou have liver impairment?
Nsaids
Metoformin
Warfarin
Benzodiazepines
Can you predict type B ADR?
No, immune or genetic factors
Management of type B ADR?
Stop causative agent
Deal with the ADR
What is type C ADR?
Chronic
Are type C ADR predictable?
Predictable form known pharmacology
What are examples of type C chronic ADR?
Osteoporosis of the jaw with bisphosphonates
Osteoporosis with long-term high dose steroids
When can you notic type C chronic ADR?
Effects require prolonged period of exposure to develop
Management of type C ADR?
Use prophylaxis
Monitoring
What is type D ADR?
DELAYED
What is type d ADR?
Effects do not arise until prolonged period of exposure
Even though drug withdrawn it may still have effects in the future
E.g. chemo therapy… increased risk of lymphomas in later life
Type E ADR?
End of use
What is type e ADR?
Effect seen on medicines withdrawal: withdraw reactions
What drugs do you see type E ADR with?
Benzodiazepine
Opiates
SSRI
Steroids
Beta blockers
General prophylaxis for ADR?
Avoid certain medicines for high risk pt
Consider reducing dose - check BNF
Monitor side effects
Offer prophylaxis
Avoid known drug interactions
What is pharmacovgilance?
The process involving detection, assessment, understanding and prevention of ADRs
Continual assessment o the risk and benefits of each drug resulting in th best drug therapy for pt
Main metho for post-marketing surveillance of ADR in UK?
Yellow card scheme
What does the yellow card scheme for collect information on? (5)
Side effects (AKA ADR)
Medical device adverse incidents
Defective medicines (those that are not of an acceptable quality)
Counterfeit or fake medicines or medical devices
Safety on Erin’s e.g. e-cigarettes or their refill containers
Information to include on a red card report?
Cytochrome P450 inhibitors?
Omeprazole
Erthyromycin
Isoniazid
Ethanol
Sulphonamides
Disulfiram
Valproate
Cytochrome p450 inducers?
Alcohol
Barbiturates
Carbamezepine
Phenytoin
Rifampicin
Pts susceptible to ADR?
Elderly
Renal impairment
Diabetes mellitus
Epilepsy
Young
Critically ill
Pts undergoing complicated surgical procedures
Due to polypharmacy
Agonistic interactions of drugs?
Blood pressure of ramipril and idapamide
Increased sedative effect wen ethanol and diazepam are combined
Antagonistic effect of drugs example?
Atenolol and salbutamol
Naloxone and morphine
Pharmacokinetic drug interactions?
When one drug affects the absorption istrinution, metabolism or exertion of another
Drug interaction which affects proetin binding and distribution?
E.g. drug A displaces drug B from the carrier proetin then there is an increase in active drug B
E.g. amiodarone displaces digoxin and can lead to digitoxicity
Drug interactions in relation to metabolism?
Drug A induces/inhibits the enzyme metabolism of drug b
E.g. metabolism of warfarin is inhibited by amiodarone leading to an increase in anticoagulan effect of warfarin
Cytochrome p450?
Microbial enzyme found in the liver and gut
Metabolises many dugs
Where are the majority fo drugs excreted?
Kidneys
What drug can make increase risk of methotrexane toxicity and why?
NSAIDS
Competition for renal tubular excretion
