Psychiatric Medication - anxiolytics Flashcards
Examples of anxiolytics
- Beta blockers
- Benzodiazepines
- Pregabalin
- Antidepressants
Beta blockers for anxiety MOA
- Affect bio-psycho-feedback - interrupt cycle of brain affecting behaviour
- For when nerves affect performance
- Limited effectiveness
Danger of propanolol
- Overdose
- Can cause arrhytmias
- Contraindicated in asthma
What kinds of people often can misuse beta blockers?
- Professional musicians
- Snooker players
- Actors
Benzodiazepines use
- Diazepam (long hald life)
- Lorazepam (shorter half life, more dependence forming)
- Bind to GABA receptors to potentiate effect of GABA - positive allosteric modulators = neurones less excitable
Risk of benzodiazepines
- Tolerance and dependence - max use 6 weeks sometimes recommended, but can be used for longer if non dependence issue (usually short term)
- Significant potential for misuse - use for single event - need trial run previous to this (check sedation and PD, potentiates alcohol - avoid)
- Occasionally can cause paradoxical disinhibition
What is paradoxical inhibition?
- Give something to make someone calm and it actually makes someone become more agitated
- Often seen in lower doses in people of older age
- Amygdala root of emotional processing, frontotemporal region controls how much the emotion is shown - knock out FT but amygdala remains
MOA pregabalin
- Binds to voltage gated calcium channels on neurones
- Reduces neuronal activity (CNS depressant)
- Used for anxiety, neuropathic pain and epilepsy
Risk of pregabalin
- Less potential for misuse and dependence and tolerance than benzos
- But still misused - chopped up and sniffed
- BNF says should be short term
- Sedation
- Weight gain
First line meds for anxiety
- SSRIs
Examples of hypnotics - sleeping tablets
- Benzodiazepines - Temazepam, Lormetazepam, Nitrazepam
- Non-benzodiazepines - still allosteric positive modulators of GABA but structured different eg Zopiclone and Zolpidem (also called Z drugs)
Benzos vs nonbenzodiazepines hyponotics
- Not much difference between two groups
- Z groups often favoured
- Both significant potential for misuse, dependence and rebound insomnia
What is rebound insomnia
- Sleep disturbance that occurs when person stops taking sleeping medication
- Becomes worse than it was before starting medication
Max duration of hypnotics
- Only for 2 weeks
- Take for only 5 out of 7 days each week - reduce potential tolerance (get receptor downregulation)
Mood stabilisers
- Used for bipolar disorder
One of:
* Lithium - one of most effective mood stabilisers
* Anticonvulsants
* Second generation (atypical) antipsychotics
Lithium MOA
- Unknown - does lots of thinks
- Lowers noradrenaline release and increases serotonin synthesis
- Also used to augment antidepressants
Cautions with lithium
- Narrow therapeutic window
- Need regular serum levels - weekly after dose change intil level stable
- Then 3 monthly once stable
- Entirely excreted by kidneys (none metabolised by liver)
Lithium effect on suicide
- Significant evidence that it reduces suicide
- Has a licence for this
- Can be given to suicidal people (eg with EUPD)
Side effects (short term) lithium
- GI disturbance (esp on initiation)
- Metallic taste in mouth (is metal)
- Dry mouth
- Fine tremor
- Polydipsia
- Polyuria
- Weight gain
(usually give at night, can cause anuresis)
Long term effects Lithium and monitoring
- Hypothyroidism - reversible (can stop drug or give levothyroxine and continue)
- Renal impairment - irreversible, occurs mostly above therapeutic doses
- THEREFORE - need annual U&Es and TFTs
- Lithium level every 3 months (via lithium register)
Symptoms of lithium toxicity
- Confusion
- Coarse tremor
- N+V
- Ataxia
- Seizures
Management of lithium overdose
- Stop lithium
- IV fluids
- Dialysis if needed
- Benzodiazepines if seizures
What can increase risk of lithium toxicity?
- Dehydration - advise to drink lots of water in hot climates
- Lithium does not come out in sweat
Drug interations with lithium
- NSAIDs - if increase NSAIDs, lithium levels likely go up
- Loop diuretics
- ACE inhibitors
If change dose of one, may affect the concentration of other