Session 14 Flashcards
- Appreciate the range of poisons that can be taken / administered
- Recognise how unwell poisoned patients may present to hospital
- Have knowledge of the general management of patients with poisoning
- Know how paracetamol can cause hepatotoxicity
- Understand the importance of appropriate adoption of guidance in managing
- Understand how patient variability can impact on prescribing e.g. differing
- Appreciate the limits of clinical trials • Know the common causes of medication error
- Understand why elderly patients are more at risk of polypharmacy
- Learn how to minimise your future risk of prescribing errors
- Know the rules of prescribing
- Be able to identify medical errors on drug charts
- Appreciate how to prescribe drugs including antibiotics, insulin, warfarin, individual patients dose-response opiates and IV fluids.
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• Appreciate the range of poisons that can be taken / administered LO
How do you Classify drug poisoning?
Intended
• Alcohol
• Illicit drugs
• Deliberate self harm
Unintended
• Older people – iatrogenic (prescribed)
• Younger people - paracetamol
• Appreciate the range of poisons that can be taken / administered LO
Give examples of common UK poisons
- Paracetamol
- Hypnotics (diazepam, zoplicone)
- Salicylates
- Ecstasy
- Amitriptyline (tricyclic)
- Opiates
- Other anti-depressants
- Cocaine
• Recognise how unwell poisoned patients may present to hospital LO
- What clinical findings may a poisoned patient present with?
- Neurological signs poisoned patients may present with?
(• May be obvious • Might be concealed - do not want to tell you • Coma)
- • Alcohol/solvents on breath
• Needle track marks
• Blisters (barbiturates) - UMN signs (anti-cholinergics)
• Hypertonia
• Hyperreflexia
• Extensor plantars
Coma (many)
• Decerbrate/decorticate posturing
Dystonic (means: abnormal muscle tone -> muscle spasm and abnormal posture) movements (metoclopramide)
• Recognise how unwell poisoned patients may present to hospital LO
- What pupil signs might a poisoned patient present with? (state medical term)
What poisons can produce these signs?
Dilated pupils – ‘mydriasis’
• Anti-cholinergics (TCAs)
• Sympathomimetics (amphetamines)
• Blindness (quinine, ethanol)
Constricted pupils – ‘miosis’
• Opiates
• Nerve agents (e.g. VX)
• Recognise how unwell poisoned patients may present to hospital LO
- How may the ventilation of a patient who has been poisened change? State the poison which would cause these changes?
- How may blood gases change? State drugs which can cause this change?
- Hypoventilation
- Opiates
- Carbon monoxide poisoning
Hyperventilation
• Salicylates
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Acidosis
• Respiratory (hypoventilation)
• Metabolic (ethanol)
Alkalosis
• Respiratory (salicylates)
Hypokalaemia (β agonists)
Hyponatraemia (ecstasy)
Hypoglycaemia (insulin, alcohol)
Guess cause
Check pupils
If constricted - needle tract marks - opiates
Case History 2
- 82 year old female
- Thin and frail
- New confusion
- Disorientated in time, place and person
- Daughter available
Drug, sepsis, stroke, wide differential diagnosis
Normally on wide range of drugs
Difference in RR interval -> irregular
No p waves
Likely to be a fib
Then slurry st segment
T wave inversion - reversed tick
Renal failure
Evidence of hypokaleamia
Highly likely she is taking digoxin
Digoxin is removed through kidneys less removed so further effect
• Recognise how unwell poisoned patients may present to hospital LO
• Have knowledge of the general management of patients with poisoning LO
What drugs can be used as antidotes
Digibind - digoxin overdose
Flumazenil - barbiturates
Atropine - Organophosphate poisoning, Bradycardia secondary to drugs on the AV node:
• Know how paracetamol can cause hepatotoxicity
How is paracetamol normally metabolised?
How is paracetamol metabolised in an overdose?
- In substantial overdose, the conjugation of NAPQI is saturated leading to increasing toxic levels of NAPQI
- Therefore treatment is to replace Glutathione i.e. N-acetylcysteine (Parvolex)
What determines whether we give the patient who has overdosed with paracetomol charcoal/ n-acetylcysteine
If seen within 0-4hrs since overdose give activated charcoal orally
Blood test taken at 4hrs
Determine if they fail below(do not need treatment) or above they do need treatment
- What complications can we anticipate by giving ANFiDoG?
- Follow-up care? (3)
- • Violence
- Hypothermia
- Hyperthermia
- Convulsions
- Rhabdomyolysis
- Urinary retention
- • Usually self-limiting
• Some will be recurrent
• Psychiatric services
• Understand the importance of appropriate adoption of guidance in managing individual patients LO
What is this graph showing?
- Dose-Response Curve
- Responders v. Non-Responders
- Genetic Influences on Drug Metabolism
- Competitive v. Non-Competitive antagonism
Same drug but different patients
Drug is effective for each patient but different doses
• Understand how patient variability can impact on prescribing e.g. differing dose-response LO
What is this graph showing?
Different patients
Even if you increase dose some patients will and will not respond
Genetic Influences on Drug Metabolism
Influences on Response to Drug Therapy
How does the fact that genetic status plays a role in drug metabolism link to the ADRs of ACE-I?
how do we figure out which drugs are ACE-inhibitors
Polymorphism in the bradykinin receptor gene so only some individuals might develop a cough
PRIL ACE-I
- β-Blockers should be given in low dresses to who and why?
- What other drug can be given at lower dose to these individuals?
- What is this image showing?
- Black & white individuals
lower no. Of CYP2D6 which metabolises the drug
drug can be given at lower dose to have the same effect
otherwise will have an ENHANCED response to the drug
- antidepressants & opioids
- Adrenal gland - pheochromacytoma pumps out adrenaline & noradrenaline
• episodic high bp and tachycardia
treated with a/beta blockers
otherwise resection
What are these graphs showing
• Know the common causes of medication error LO
- What is medication error?
- Give examples
-
preventable event that may cause, or lead to inappropriate medication use or
* *patient harm** while the medication is in the control of the health care professional, patient or consumer
At point of:
• Prescribing • Dispensing • Administration
- • Clarity of handwriting / spelling
- Ridiculous self-imagined abbreviations
- Inappropriate dosing for route of administration
- Transcription from inpatient to TTO (to take out) or one chart to another
- Inhaled therapy (wrong route)
- Unclear drug units
- Loading dose regimens e.g. amiodarone
- Alternative day therapies
- Ineffective cancellation of prescriptions or lack of end date (e.g. antibiotics)
- Controlled drug prescriptions
- Failure to review the ‘drug chart’ regularly
• Understand why elderly patients are more at risk of polypharmacy LO
- What is polypharmacy?
- Polypharmacy: why is there a greater risk of polypharmacy elderly patients?
- Changes to drug PK/PD in the elderly?
- • Use of multiple medications by a patient
(• Excessive or unnecessary prescriptions
- Practice of prescribing 4 or more medicines to the same person
- Remember: it can be beneficial! Not all conditions are managed with a single prescribed medicine.)
- • Multiple co-morbidities
- Worsening of co-morbidities with age
- Resident in Nursing/Residential home
- Hospitalisation
- Patient’s (and relatives’) expectations
- Poor understanding of patient regarding their medication regimen
- Consultation with multiple healthcare practitioners
- Poor knowledge of prescriber regarding prescribing in the elderly
- Image
• Learn how to minimise your future risk of prescribing errors LO
- How can we minimise inappropriate prescribing?
- Sources to aid prescribing
- Before Prescribing: Drug History
- Follow principles of good prescribing (AGE, OTHER DRUGS, COMORBIDITIES, CONTRAINDICATIONS, allergies)
- Be meticulous (• Use your mind, not just your pen • Legible Writing • Avoid Abbreviations • Review, review, review • Clarify instructions • Check your prescription)
- Use formularies / guidelines appropriate to your patient (• Use familiar drugs wherever possible • Look up unfamiliar drugs:•Interactions with other drugs • Interactions with diseases)
- Advice to patient etc
- Utilise tools e.g. STOPP/START for older persons
- Involve pharmacist / nurses e.g. communication / patient medicine adherence
- • BNF (Current Edition) / BNFc • Leicestershire Prescribing Guide • Leicestershire Medicines Code • IV monographs • Guidelines e.g. BTS, Trust guidelines e.g. CAP • SPC • Specialist sources • Search engines / journals • Pharmacist
- • Sources of drug history
- Include allergies!
- Review need for regular treatment mindful of admission:
- No longer indicated
- Regular treatment now contraindicated
- Concern over new drug-drug interactions
- Dose change e.g. acute kidney failure
What is metabolised by the kidney?
MORPHINE
• Know the rules of prescribing LO
- What are the rules of prescribing
- How to Prescribe?
- Check (sources)
- Clarity of handwriting (legible)
- Black ink
- Legible
- PRN (when necessary) medications – indication, frequency and maximum dose
- Changes to Rx (to take/prescription) – rewrite in full, sign and date changes, document in notes (good practice)
- • Addressograph sticker
- Allergy box - red
- Generic names
- Drug, route, dose, strength, frequency
- Abbreviations (avoid)
- One route
- Dose – g, mg etc - caution with microgram
• Liquids – prescribe in “mg” not “mls”
- more than one strength of syrup
• Be able to identify medical errors on drug charts LO
• Appreciate how to prescribe drugs including antibiotics, insulin, warfarin, opiates and IV fluids LO
- What drug chart is this showing?
Community
DO CPPT session 14
