Lecture 17: Drugs of Abuse Flashcards
Define substance dependence syndrome - abuse vs dependence (ie addiction)
Symptoms of
- Continued use despite substance related problem,
- tolerance,
- withdrawal symptoms
1 or 2 symptoms= abuse
3= substance dependence
What is tolerance, what is it caused by and what is the opposite
Tolerance is when the dose needs to be increased to get the same effect over time.
Due to receptor downregulation/ increased metabolism/clearance
Sensitisation is opposite
What parts of the brain do addictive drugs target
Increase dopamine + serotonin,+ NE in the Mesolimbic dopamine system.
This is midbrain to nucleus accumbens involved with learning, reinforcement of pleasure. This causes a feedback cycle which leads to dependence on the level of monoamines
Define withdrawal syndrome - evidence of physical dependence
Autonomic ns syndrome overdrive due to removal of drug. Each drug class has specific symptoms.
Eg. Opioid: restless, sensitive to pain, sweating, tachycardia,
What features of the drug make the user want to use again (associated with increased central neurotransmitters)
- more Rapidity of onset.
- Less Presence of withdrawal syndrome,
- more convenient and effective method of administration
What are the user aspects make susceptible to substance dependence
- Addictive personality
- Anxiety, depression, psychiatric disorders
- stress, insomnia
- Environmental peer pressure
Give examples of stimulants, mixed and depressants drugs of abuse
Stim: amphetamines, cocaine, LSD, ritalin, caffeine, benzadrine. MDMA ecstasy, BZP,
Appetite suppressant, CNS increase of DA, NA, 5HT
Mixed: ketamine, synthetics
Depressants: like a strong anaesthetic. alcohol, cannabis, opioids, benzodiazepines
What is the pharmacokinetics of elimination of alcohol
With small concentrations it goes down by first order kinetics in an exponential way but after 2-3 standard drinks, there is saturation of the system and it follows zero order kinetics: linear decline
What to do in severe acute intoxication with alcohol
- Supportive ABCDE
- Ventilation
- Dialysis
Don’t assume they are just drunk - Test blood ethanol, drug levels and rule out trauma other things that could cause the symptoms
Which is more prevalent, prescription opioids or illicit?
What is abuse potential related to
Prescription opioids - sending patients home with opioid- have become a gateway for accidental overdose with illicit -ie fentanyl, heroin (diamorphine)
AP: lipid solubility and euphoric high.
eg. Methadone used for weaning programs, less soluble- long action, slower onset
What is the action of opioid receptor
Opioids can be agonists, partial agonists or antagonists of this receptor
The opioid receptor is in the cell membrane. It inhibits adenyl cylcase therefore reducing intracellular transmission (cAMP, ca2+) causing reduced neurotransmitters for pain messenging
What are the bad effects of opioids
Good are analgesia, sedation, cough suppression
Respiratory depression
constipation, nausea, vomiting,
down symp system: hypotension, bradycardia, pupillary constriction
Psychological craving for opioids.
What is the analgesic ladder
1st visit: non opioid + adjuvant (eg. paracetamol + ibuprofen
2nd: mild opioid + 1st visit (eg. tramadol)
- AT this point its good to refer to chronic pain specialist to avoid addiction
3rd: moderate to severe pain opioid
What is cocaine made of, and its function - stimulant
Coca leaves. Crack cocaine + baking soda and water= rapidly absorbed.
It is a local anaesthetic and vasoconstrictor by potently inhibiting catecholamine re uptake -> massive rush of NA, DA, 5HT.
What are common effects of stimulants
for amphetamines psychological dependence>physical
Euphoria, libido, self esteem, confidence
increase Symp NS;
seizures, cardiotoxicity: arrhythmia, hypertension, MI, renal failure, stroke, death
^ aggression, grandiosity, restlessness,
^psychosis, hallucinations
