Exam

Question 1

Briefly summarise an evidence based approach to responding to cannabis dependence. Your answer should include reference to the UK/English current guidelines.

Answer 1

CBT
Motivational interviewing 
Contingency management
The support worker will have a KEY role
Drug therapy can be used to address symptoms such as anxiety and insomnia

Question 2

Briefly describe the pharmacological basis for why oral methadone can be an effective replacement therapy for heroin addiction.

Answer 2

Methadone:
- Full mu-opioid receptor agonist
- Slow onset of action when taken orally
- Long elimination half-life (24-36 hours) allows it to be used either as a maintenance therapy or detoxification agent.
 This is the result of a slow metabolism and very high fat solubility.
- NMDA receptor antagonist: acting as an NMDA antagonist may be one mechanism by which methadone decreases craving for opioids and tolerance by disrupting memory circuitry.
 Receptor antagonist against the primary excitatory neurotransmitter in the brain glutamate.

Question 3

What is buprenorphine?

What is naloxone?

Answer 3

B: partial agonist at the mu receptor with a slow onset of action and long duration of action allowing for alternative day dosing.

The disadvantage of B is that the partial agonist activity my limit its maximum efficacy and low dose treatments are rubbish for retaining people in treatment.

Naloxone is a pure opioid antagonist at mu and used with B in a 1:4 ratio to reduce abuse liability.

Question 4

What is naltrexone?

Answer 4

oral, long acting, antagonist for mu.
no psychoactive properties other than blocking mu receptor.
Bettter for long term treatment and naloxone is used for emergency od treatment.

Question 5

Why might naltrexone be useful in alcohol dependence?

Answer 5

Naltrexones action in alcohol dependence is not well understood, but as an opioid receptor antagonist is likely to be due to the modulation of the dopaminergic mesolimbic pathway/reward pathway activated by all drugs of abuse. The mechanism of action may be antagonism to endogenous opiates such as tetrahydropapaverlonie, whose production is augmented in the presence of alcohol.

Could be used in depression and alcohol use.