Substance misuse and Alzheimer's Flashcards
What type of drug order elimination does alcohol undergo?
Zero order elimination
What is zero order elimination?
In zero-order kinetics, the rate of drug elimination is constant regardless of the concentration of the drug in the body.
Example: Alcohol metabolism follows zero-order kinetics. No matter how much alcohol is consumed, the body can only metabolize it at a certain rate per unit of time.
What are the inhibitory actions that occur with alcohol consumption?
Potentiates inhibitory GABA
Inhibits excitatory glutamate
What are the excitatory actions that occur with alcohol withdrawal?
Restlessness
Tremor
Anxiety
Tachycardia/hypertension
Seizures
Delirium tremens (confusion/hallucinations) = EMERGENCY
What is the typical timeframe for delirium tremens?
As early as 48 hours after abrupt cessation of alcohol in those with chronic use and can last up to 5 days.
A build up of what substance results in alcohol hangover?
Acetaldehyde
Alcohol is inhibitory and alcohol withdrawal is excitatory meaning that alcohol withdrawal should be treated with inhibitory medications. True/false?
True
Excitatory features associated with an alcohol withdrawal state?
Restlessness
Tremor
Anxiety
Tachycardia/hypertension
Seizures
Delirium tremens
What inhibitory medications are used in alcohol withdrawal?
Benzodiazepines
Diazepam (long acting) = preferred
Lorazepam (short acting) = if acute (e.g. DT-delirium tremens)
Carbamazepine
If benzos contraindicated
Clomethiozole
3rd line (respiratory depression if taken with alcohol)
When are benzodiazepines contraindicated?
Because of their muscle relaxant action, benzodiazepines may cause respiratory depression in susceptible individuals.
So contraindicated in:
Myasthenia gravis
Sleep apnea
Bronchitis
COPD
Differences in features between Wernicke’s encephalopathy and Korsakoff syndrome?
Wernicke: acute thiamine deficiency (ataxia, nystagmus, confusion),
Korsakoff: chronic thiamine deficiency (dementia, confabulation)
What are confabulations in Korsakoff syndrome?
Fabrication of imaginary experiences as compensation for loss of memory.
What are symptoms of opiates?
Analgesia
Sedation
Euphoria
Constipation
Nausea
What are features of opiate toxicity?
Unconsciousness
Respiratory depression (slow or shallow breathing causing poor gas exchange in alveoli).
Pin point pupils (constricted pupils)
What drug is used to reverse opioid toxicity?
IV naloxone
What are options for opiate substitution therapy?
Methadone:
Full mu opioid agonist
Oral solution
Buphrenorphine:
Partial mu opioid agonist
Oral tablet
What are the main hallmark’s of Alzheimer’s dementia?
Cortical atrophy (wide sulci and narrow gyri).
Neurofibrillary tangles (abnormal tau protein accumulation in the neurons).
Senile plaques (polymorphous beta-amyloid protein deposits found in the brain in Alzheimer disease and normal aging).
Features of opiate intoxication?
Drowsiness
Confusion
Decreased respiratory rate
Decreased heart rate
Constricted pupils
Track marks (needle marks) - applies if IV route has been used.
- Abscess at injection sites
- Veins thrombosed and damaged causing difficulties with IV access.
Opiate withdrawal is life threatening. True/false?
False
Unlike alcohol withdrawal, opiate withdrawal is NOT life threatening.
What are some of the features of opiate withdrawal?
Agitation
Anxiety and irritability
Chills
Runny nose
Piloerection (“goosebump” hairs)
Dilated pupils
Increased blood pressure and heart rate
GI disturbances (i.e. abdominal cramps, nausea, vomiting and diarrhoea).
During opiate withdrawal, what drugs can help to treat symptoms?
Methadone: may cause prolonged Qtc
Loperamide (for diarrhoea)
Anti-emetics (for nausea
When does alcohol withdrawal symptoms usually become apparent?
Onset usually 12 hours after last drink.
Characteristic features of alcohol withdrawal?
Nausea and vomiting
Tremor
Sweating
Anxiety
Agitation
What is delirium tremens and when does it usually occur?
A life threatening medical emergency, and usually occurs at day 3 of withdrawal, and lasts 3 days
What are characteristic features of delirium tremens?
Characterised by:
Paranoid delusions
Visual/auditory and classically haptic (tactile) hallucinations (sensation of crawling e.g. formication)
Seizures
What is typical management of delirium tremens?
Oral lorazepam as first line, and if the oral route cannot be used for whatever reason, parenteral lorazepam or haloperidol.
What is used for prevention and treatment of alcohol withdrawal?
Short-acting benzodiazepines i.e. chlordiazepoxide and oxazepam (if evidence of liver injury).
What is supportive treatment of alcohol withdrawal?
Fluids
Anti-emetics
Thiamine (i.e. pabrinex) - which is vitamin B1
What does wernicke-korsakoff cause in the brain?
Mammiliary body atrophy
What is Wernicke’s encephalopathy?
Reversible presentation (treated with high dose IV thiamine e.g. pabrinex).
Characteristic features of Wernicke’s encephalopathy?
Confusion
Ataxia
Ophthalmoplegia
Nystagmus
Less clinical features include: urinary incontinence and hypothermia due to autonomic neuropathy.
What is Korsakoff’s psychosis?
An irreversible manifestation of untreated Wernicke’s encephalopathy.
Characteristic features of Korsakoff’s psychosis?
Retrograde amnesia (loss of memory before incident)
Anterograde amnesia (inability to make new memories)
Confabulations (fabricate imaginary experiences as a compensation for memory loss)
