14.1 Poisoning And STOPP-START Flashcards
What should be checked when thinking about medicine optimisation?
Checking repeat prescriptions
Full medication review - discussing each medicatio and condition with the patient
Ensure patient is taking the medications at the right time
Ensure they are taking medication in the intended way
Improving clinical outcomes - make sure it is the most beneficial and appropriate drug
Improve economy - best investment for each pound
Why is it useful to do medicine optimisation?
Because of polypharmacy - patients may be taking 4-6+ medicines a day
ADRs and DDIs are a common reason for admission to hospital in the elderly
What patients should be targeted for medication review?
- Taking lots of medications - polypharmacy. The more drugs a patient is taking, the less good their adherence is likely to be
- Complex medication regimens - taking drugs in a particular way at a particular time of day
- Recently discharged (or admitted)
- Frequent admissions to hospital - could be related to more management of their medications
- Comorbidities
- Medications prescribed from multiple sources
- High risk medications – narrow therapeutic window, known and serious side effect profile
What are some of the pharmokinetic and dynamic changes in older people to think about when reviewing medication?
- Body composition – increased fat, decreased body water and lean mass
- Renal mass and function reduced
- Hepatic function and blood flow decreased
- GI absorption decrease, GI bleed risk increase
- Baroreceptor sensitivity reduced - older patients tend to increase cardiac output instead of heart rate
- Reduced first pass metabolism
- Protein binding
- Receptor expression level changes
- Psychotropic drugs and extra pyramidal effects
Who might carry out a medication review?
GP
Hospital doctors
Specialist pharmacists
What things should we be thinking about when conducting a medication review?
Is the medication right for the patient Time limited medication Age - life expectancy and risk/benefit Measureable outcomes - able to tell whether or not the medication is effective Cost Appropriate tests to support decisions
What is the function of the STOPP-START tool?
To aid in medication reviews
screening tool of older people’s prescriptions and screening tool to alert to right treatment
What group of people is STOPP-START used for?
Polypharmacy patients over 65
What is the aim of the STOPP-START tool?
Aim to highlight and prevent inappropriate prescribing → reduction in DDIs and or ADRs
What is the difference between drug toxicity and adverse drug reaction?
ADRs are typical of a drug being used at therapeutic doses
Drug toxicity more commonly associated with effects that occur at supra therapeutic doses - giving doses of an agent well above what we know causes a therapeutic benefit
What causes pharmalogical toxicity?
Most often predictable extension of desired effect
Secondary effect not related to primary aim of the treatment
An effect normally only seen in large overdose - too much drug, narrow therapeutic window
What drugs can cause pharmalogical toxicity in overdose?
B-blocker - myocardial depression
Opioids - respiratory depression
Theophylline - convulsions, arrhythmia
Carbamazepine/phenobarbital - respiratory depression
What is meant by biochemical toxicity?
A drug or active metabolite which causes cellular damage - macromolecules inc. structural proteins and enzymes.
How does biochemical toxicity occur?
Potentially harmful metabolites build up. If they are not inactivated they can cause cytotoxicity.
Balance of elimination of a drug or metabolites will dictate the potential harm that may be caused
How do we overcome biological toxicity?
Development of suitable pharmacological treatment.
Give an example of overcoming biological toxicity during overdosing
Acetyl cysteine - think donating in paracetamol overdose administered in three successive infusions at different concentrations over 21 hours.
Give an example of overcoming biological toxicity at therapeutic levels
Cyclophosphamide used in severe RA produces highly toxic metabolites eliminated in urine. Can cause haemorrhagic cystitis due to damage to the bladder
Use Mensa alongside cyclophosphamide as has a thinly group for cytochrome toon and polar group. Also aggressive hydration
What resources can we use to check biological and pharmalogical toxicity?
BNF
TOXBASE
What are the 5 overdose management principles?
Prevention of absorption Immediate actions Supportive measures Enhance elimination Antidotes
What are the immediate actions we can consider during an overdose?
Remove person from contact with the poison
Vital signs and injury
History
Evidence
What are the supportive measures we can address in the event of an overdose?
Cardiac arrest = support any hypoxia, electrolyte and metabolic disturbance and cardiac toxicity
Arrhythmias = support hypoxia, electrolyte and metabolic disturbance and cardiac toxicity
Hypotension = support myocardial depression, peripheral vasodilation
Renal failure = hypotension, direct nephrotoxicity, rhabdomyolysis
Respiratory failure = direct neurotoxicity
Hepatic failure = direct hepatotoxicity
Seizures = hypoxia, direct neurotoxicity
How do we prevent absorption in overdose?
Activated charcoal in large quantities. Not suitable for drowsy or comatose patients
Why is gastric lovage not used in overdose?
Due to risk of aspiration
How do we manage elimination in overdoses?
Continued activated charcoal
Sodium bicarbonate - alkaline diuresis
Haemodialysis
Give some examples of competitive antagonist antidotes?
Naloxone
Atropine
What are chelating agents?
Agents that form a complex with a drug to reduce the free drug. Used in overdose as an antidote. Some examples of overdose with cyanide lead and iron salt poisoning.
Give some examples of drugs that work as an antidote via manipulating drug metabolism
Fomepizole
Acetylcysteine
Give some examples of specific antidotes
Antibodies
Antivenoms
Digoxin-specific antibody
