Which is more addictive... Morphine or Heroin?
Why is heroin more addictive than morphine?
It crosses the blood brain barrier more quickly = quicker and more effective 'high'
Which three drugs do we use to treat heroin addiction?
- Methadone maintainance (agonist of receptor)
- Buprenorphine (+ naloxone = stops potential for abuse)
- Safe controlled heroin supply (reduced chances of infection etc.)
How does opioid abuse affect analgesia?
Opioid analgesics = (e.g. morphine & codeine)
- Addicts have tolerance = need higher than clinical dose to be effective
- More likely to start abusing again if given
Which analgesic should you use to treat an opioid abuser instead?
(κ agonist & μ antagonist)= analgesia
= withdrawal effects by blocking μ & no euphoria so less likely to become addicted
What do indirecting acting sympathomimetic drugs do?
mimic activation of SNS but dont actually activate the receptors= increased dopamine in synapse
Where does Cocaine act in the synapse?
Blocks dopamine reuptake
Where does Amphetamine and Methamphetiamine act in the synapse?
Amphetamine transported into neurones = release of Dopamine
Inhibits dopamine degradation by monoamine oxidase (MAO)Stimulates dopamine release
What are the two forms of cocaine?
Cocaine hydrochloride (nasal inhalation or IV administration)
Crack cocaine (insoluble! smoked = vaporises at 90 degrees) -> crosses membranes in blood more readily = free base form
How is crack cocaine produced from Cocaine hydrochloride?
Heat up cocaine hydrochloride with bicarbonate
What are the 9 Amphetamine acute side effects?
- Elevated mood
- Increase alertness
- Increased stamina
- Increased heart rate
- Raised blood pressure
What are the 6 post drug amphetamine side effects?
- Psychiatric disorders
- Sustained effects on BP
Where does Ecstasy (MDMA) act in the synapses?
Causes 5-HT release
Inhibits 5-HT reuptake
Why do we combine MDMA with Prozac?
- MDMA is immediate (doesn't take weeks for effect)
- MDMA can cause neurodegeneration (blocked by prozac)
What are the 5 extra acute effects of MDMA than amphetamine?
- Perception disruption
- increases body temp
- allergic reactions
- 5-HT syndrome (massive 5-HT release = headaches & dizziness)
N.b. the rest are the same as amphetamine but NO aggression with MDMA
What are the 2 extra post drug effects of MDMA than amphetamine?
N.b. also fewer cardiovascular effects
What are the active components of cannabis sativa (cannabis leaves)?
What s the main psychoactive (CNS) constituent of cannabis?
THC = Δ 9 tetrahydrocannabinol
Which receptors does cannabis act on?
CB1 & CB2 receptors
Which receptor that cannabis acts on is responsible for the CNS effects of the drug?
What type of receptors are CB1 & CB2?
= increase K
Name an endogenous agonist of CB1 & CB2:
List the 8 acute effects of cannabis:
- Feeling unwell
- Perceptual change e.g. time
- lowered temperature
- increased heart rate
- anti-emetic (stops feeling sick)
- Appetite stimulation
Why is cannabis not very addictive?
No reported withdrawal syndrome (no severe effects)
If cannabis is not addictive then why do some people keep taking it (2)??
- physiological addiction (want the feel good experience again)
- A-motivational syndrome (less motivated when taking it = find it more difficult to change their behaviour)
What is the most highly expressed GPCR in the brain?
n.b. we don't understand exactly what it does
Can long term cannabis use cause irreversible cognitive decline?
- cognitive decline while under influence & some if smoked for long periods of time (irreversible)
Not absolute proof though
Can cannabis use cause schizophrenia?
- Stronger cannabis (skunk) but incidence of schizophrenia not increased at same rate as strength of cannabis
- may be link that those more likely to develop schizophrenia are also more likely to take cannabis
Name a CB1 receptor antagonist:
What were the problems with the CB1 receptor antagonist Rimonabant?
Induced depression and other psychological disturbances = not used clinically
Which possible uses was rimonabant clinically trialled for?
(animal studies decreased ethanol consumption & heroin and cocaine relapse)
How many groups of Hallucinogens are there?
Name two group 1 hallucinogens:
- LSD (Lysergic acid diethyl amide)
What type of drugs are group 1 hallucinogens?
5-HT2A receptor agonists
Name two group 2 hallucinogens:
- PCP = phencyclidine/ 'angel dust'
- Ketamine (anaesthetic for children and animals)
What type of drugs are group 2 hallucinogens?
NMDA receptor antagonists
What are the 6 acute effects of hallucinogens?
- altered sensations
- visual distrubances
What are the 3 main withdrawal symptoms?
- Panic attacks
- Psychiatric disturbances