Pharmacotherapy for Drug and Alcohol Misuse Flashcards Preview

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Flashcards in Pharmacotherapy for Drug and Alcohol Misuse Deck (50)
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State the four uses of pharmacotherapies in addiction

Substitution, treating withdrawal, preventing relapse, and preventing harms


What percentage of alcohol dependent patients are not treated? (Kohn et al, 2004)

92% - mostly as they do not seek treatment


Are substitutions ever prescribed for alcohol?

No - but theoretically diazepam or valium could be, as they are very similar in their effects


Why should alcoholics not go cold-turkey outside of hospital?

Alcohol withdrawal is life-threatening and they could suffer seizures


How many major subunits does the GABA-A receptor have?



How does chronic drinking affect the GABA-A receptor?

It causes receptor tolerance, probably by changing the subunit profile


How does chronic drinking affect the NMDA receptor?

Alcohol antagonises the NMDA receptor. Chronic drinking leads to receptor upregulation to combat the antagonistic affect - in animal models, this is associated with impaired memory


Describe the effects of alcohol withdrawal on the brain

It increases activity in the NMDA receptor and L-type calcium channels, leading to calcium influx, hyper-excitability, and cell death. This increased activity causes seizures. It also causes decreased GABA-ergic activity and less magnesium ion inhibition of the NMDA receptor


Describe the effect of multiple alcohol detoxifications

Multiple detoxifications are associated with less response to treatment (Malcolm et al, 2000) and worse performance on cognitive tests (Duka et al, 2003)


Name a drug used at specialist addiction treatment centres to calm NMDA activity during alcohol withdrawal



Name the 2 drugs used to reduce signs and symptoms of alcohol withdrawal

Benzodiazepines and carbamazepine


Why is carmabazepine not used for alcohol withdrawal in the UK?

It side effects - confusion and ataxia - are the same as the symptoms of alcohol withdrawal


State some harms of long-term alcohol use

Malnutrition, liver disease, inflammation, Marchiafava-Bignami disease, central pontine myelinosis


What is Marchiafava-Bignami disease?

Corpus callosum demyelination, necrosis, and atrophy, lrading to loss of consciousness, aggression, seizures,depression, hemiparesis, ataxia, apraxia, and coma


What is central pontine myelinolysis?

A neurological condition involving severe damage to the myelin sheath of nerve cells of the pons. It is most commonly caused iatrogenically by increasing serum sodium of a hyponatraemic patient too quickly - the mechanism of damage in alcoholism is unclear


What is the most common vitamin deficiency in alcoholics?

B1 (thiamine)


State the 2 main consequences of thiamine deficiency

Wernicke's encephalopathy and Korsakoff's syndrome


Describe the triad of symptoms in Wernicke's encephalopathy

Ophthalmoplegia, ataxia, acute confusion (many patients do not have all three)


Describe Korsakoff's syndrome

Irreversible short-term memory loss in the presence of otherwise normal cognitive peformance


What is the most common presenting symptom of Wernicke's encephalopathy?

Acute confusion - which makes it hard to differentiate from acute alcohol intoxication


State a cause of Wernicke's encephalopathy other than alcoholism

Hyperemesis gravidarum


Why do alcoholics require IM or IV thiamine?

They cannot absorb sufficient from an oral route


What is the daily requirement of thiamine?



Describe the relationship between the D2 receptor, D3 receptor, and addiction

Low levels of D2 are associated with drug-liking and impulsivity and are seen in stimulant and alcohol addicts. High levels of D3 are seen in stimulant addicts but not alcoholics


Which drug of addiction is bupropion licensed for?



Describe the mechanism of action of disulfiram

It inhibits aldehyde dehydrogenase in the liver, causing a buildup of the alcohol breakdown product acetaldehyde and leading to nausea, vomiting, flushing, palpitations, headache, and hypotension


State some contraindications for prescribing disulfiram

Psychosis, severe liver disease, severe cardiac disease, epilepsy


How can disulfiram cause psychiatric side effects, and what are they?

It inhibits aldehyde hydrogenase, which is in the same family as dopamine-B-hydrozylase - the enzyme which converts dopamine to noradrenaline. It hence increases the amount of dopamine and decreases noradrenaline, leading to anxiety, mania, psychosis, and depression


Why are GABA-B agonists efficacious in alcoholism?

GABA inhibits dopamine firing in response to a stimulus and hence removes the pleasure associated with drinking


Name a GABA-B agonist that can be prescribed for alcoholism