S14) Clinical Influences on Prescribing Flashcards
How might one classify poisoning?
- Intended – alcohol, illicit drugs, deliberate self harm
- Unintended – iatrogenic (older), paracetamol (younger)
Identify five common UK poisons
- Paracetamol
- Hypnotics (diazepam, zoplicone)
- Salicylates
- Ecstasy
- Opiates
How does an overdosed patient present?
- May be obvious
- Might be concealed
- Coma
What are the clinical findings of patients who have overdosed?
- Alcohol/solvents on breath
- Needle track marks
- Blisters (barbiturates)
What are the neurological signs of overdosed patients?
- UMN signs (anti-cholinergics) – hyperreflexia, hypertonia
- Coma (many) – decerbrate/decorticate posturing
- Dystonic movements (metoclopramide)
Indicate the various effects different drugs have on the pupils when taken in excessive amounts
- Dilated pupils (mydriasis) – anti-cholinergics (TCAs), sympathomimetics (amphetamines), blindness (quinine, ethanol)
- Constricted pupils (miosis) – opiates, nerve agents (VX)
Indicate the various effects different drugs have on ventilation when taken in excessive amounts
- Hypoventilation – opiates, CO poisoning
- Hyperventilation – salicylates
Indicate which drugs are responsible for the following blood gas findings when taken in excessive amounts:
- Metabolic acidosis
- Respiratory alkalosis
- Hypokalaemia
- Hyponatraemia
- Hypoglycaemia
- Metabolic acidosis – ethanol
- Respiratory alkalosis – salicylates
- Hypokalaemia – β agonists
- Hyponatraemia – ectasy
- Hypoglycaemia – insulin, alcohol
Outline the general management for a patient presenting with a drug overdose
- ABCDE
- History (incl. collateral history)
- Examination findings
- Supportive care
- Appropriate antidotes (when indicated)
Identify some general investigations for patients with a drug overdose
- Blood
- Urine
- ECG – conduction delays, tachyarrhythmias
Identify some specific investigations for patients with a drug overdose
- Paracetamol
- Salicylates
- Other toxicology
Describe normal paracetamol metabolism
In three steps, describe paracetamol metabolism after substantial overdose as well as its treatment
⇒ Conjugation of NAPQI is saturated
⇒ Increasing toxic levels of NAPQI
⇒ Thus, treatment is to replace Glutathione i.e. N-acetylcysteine (Parvolex)
Identify six complications from paracetamol overdose and/or its treatment
- Violence
- Hypothermia
- Hyperthermia
- Convulsions
- Rhabdomyolysis
- Urinary retention
What are the influences on patient response to drug therapy?
- Genetics (20-95%)
- Age
- Organ Function
- Drug Interactions
- Nature of disease
What is a medication error?
A medication error is any 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 which three points in patient care can a medication error occur?
- Prescribing
- Dispensing
- Administration
