Substance Abuse

Question 1

Definitions - Drug Misuse, Drug Abuse, Drug Dependence

Answer 1

• drug misuse - inappropriate use of a drug
• drug abuse - self administration of a drug in chronically excessive quantities, in a manner that deviates from approved medical or social patterns in a given pattern
• drug dependence - condition in which administration of a drug is compulsively sought in the absence of a therapeutic indication and despite adverse psychological, social or physical effects
• psychological dependence / physical dependence

Question 2

Definitions - Dependence, Tolerance

Answer 2

• dependence - degree to which someone is reliant upon or influenced by a particular drug
• tolerance - condition of becoming less responsive to doses of a drug, requiring larger doses to achieve a therapeutic level

Question 3

Definitions - Toxicology, Poisons

Answer 3

• toxicology - the study of poisons

- poisons - chemical substances that can cause death or injury at low doses

Question 4

Management of Poisoning

Answer 4

• rapid and appropriate response essential
  
  • reducing absorption systemically
  • reversing and minimising effects of poisons
  • removing poisons from the body
• may include:
  
  • gastric decontamination - induction of vomiting, gastric lavage
  • absorbents, catharsis, antidotes, haemodialysis

Question 5

Absorbents

Answer 5

• activated charcoal
  
  • used to remove drugs from the GIT as a treatment for posoning
  • particles bind to molecules of ingested poisons to reduce absorption into bloodstream
  • can be used in overdose of: asprin, barbituates, tricyclic antidepresants, digoxin, amphetamines, morphine, cocaine, digitalis, phenothiazines
  • administer ASAP after oral ingestion <1hr for maximum effectiveness

Question 6

Cathartics

Answer 6

• laxative / osmotic effect
• sorbitol, mannitol
• increase pressure of intestinal contents, leading to water retention in intestine, increase bulk and increased peristalsis

Question 7

Specific Antidotes

Answer 7

• paracetamol - acetylcysteine (parvolax)
• narcotic overdose - naloxone
• heparin - protamine sulphate
• warfarin - vitamin K1 (konakion)
• digoxin - digoxin-specific antibody fragments (digibind)
• benzodiazepines - flumazenil (anexate)
• organophosphate poisoning - atropine