Mental Health Drugs Flashcards
Tricyclic anti-depressant examples
Amitriptyline, lofepramine
Tricyclic anti-depressant indications
- Second line treatment for moderate - severe depression where SSRIs ineffective
- Treatment for neuropathic pain (not licensed)
Tricyclic anti-depressant MOA
- Inhibits neuronal re-uptake of serotonin and noradrenaline from synaptic cleft, increasing their availability for neurotransmission
- Block a wide range of receptors including muscarinic, histamine, alpha-adrenergic and dopamine - accounts for extensive adverse effects profile
Tricyclic anti-depressant contraindications
Used with caution in people at high risk of side effects:
- Elderly
- CVD
- Epileptics
- Constipated
- Prostatic hypertrophy
- Raised intra-ocular pressure
Tricyclic anti-depressant side effects
- Blockade of anti-muscarinic receptors: dry mouth, urinary retention, blurred vision
- Blockade of alpha-adrenergic receptors: sedation and hypotension
- Cardiac adverse effects: arrhythmias, prolonged QT and QRS
- Neurological changes: convulsions, hallucinations and mania
- Dopamine receptor blockade: breast changes, sexual dysfunction
- Extrapyramidal symptoms: tremor, dyskinesia
- Overdose: hypotension, arrhythmias, convulsions, coma, respiratory failure
- Sudden withdrawal: GI upset, neurological and flu-like symptoms, sleep disturbance
Tricyclic anti-depressant interactions
- MOA inhibitors: both increase serotonin and noradrenaline at synapse - precipitates hypertension, hyperthermia, serotonin syndrome
- Augment anti-muscarinic, sedative, hypotensive adverse effects of other drugs
Tricyclic anti-depressant patient information
Takes a few weeks to notice improvements
Symptoms may worsen initially
Discuss psychological therapies
Treatment must be continued for 6 month minimum
SSRIs examples
citalopram, fluoxetine. sertaline, escitalopram
SSRIs indications
- 1st line for moderate / severe depression
- Mild depression after failure of psychological therapy
- OCD
SSRIs MOA
- Preferentially inhibit neuronal re-uptake of serotonin from the synaptic cleft, increasing its availability for neurotransmission
- Differ to tricyclics: do not inhibit noradrenaline uptake, cause less blockade of other receptors
- Efficacy between 2 classes similar but SSRIs preferred due to fewer adverse effects
SSRIs contraindications
Prescribed with caution where particular risk of adverse effects:
- epilepsy
- peptic ulcer disease
Young people:
- decreased efficacy
- increased risk of self-harm and suicidal thoughts
Metabolised by liver so reduced dose in hepatic impairment
SSRIs side effects
- Common: GI upset, appetite and weight disturbance, hypersensitivity reactions (skin rashes)
- Elderly: hyponatraemia which may present as confusion and reduced consciousness
- Increased suicidal thoughts and behaviours
- Lower seizure threshold
- Citalopram prolongs the QT interval so can predispose to arrhythmias
- Increased risk of bleeding
- Serotonin syndrome: when taken at high doses / combined with other anti-depressants / overdose. Triad consisting of:
-autonomic hyperactivity
-altered mental state
-neuromuscular excitation
Usually responds to withdrawal of treatment and supportive therapy. - Sudden withdrawal: GI upset, neruological and flu-like symptoms, sleep disturbance
SSRIs interactions
- MOIs: both increase synaptic serotonin levels = serotonin syndrome.
- NSAIDs / aspirin: increased risk of GI bleed, must offer gastroprotection
- Anti-coagulants: increased risk of bleeding
- Other drugs that prolong QT interval e.g. antipsychotics
SSRIs patient info
Takes a few weeks to notice improvements
Symptoms may worsen initially
Discuss psychological therapies
Treatment must be continued for 6 month minimum
Benzodiazepines examples
Diazepam, lorazepam, midazolam, chlordiazepoxide
Benzodiazepines indications
- 1st line management of seizures and status epilepticus
- 1st line management of alcohol withdrawal reactions
- Sedation for interventional procedures if general anaesthesia is unnecessary / undesirable
- Short term management of severe anxiety
- Short term management of severe insomnia
Benzodiazepines MOA
- Targets GABAa: a Cl- channel that opens in response to binding of GABA, the main inhibitory neuron
- Opening the channel allows Cl- ions to flow into cell making it more resistant to depolraisation
- Benzodiazepines facilitate and enhance the binding of GABA to GABAa
- This depresses synaptic transmission and clinically reduces anxiety, causes sleepiness and sedation, and is anti-convulsive.
- Alcohol also acts on GABAa - chronic users become tolerant to its presence. Abrupt cessation precipitates excitatory state of alcohol withdrawal. Benzodiazepines can be used to withdraw in a more controlled way.
Benzodiazepines administration
- Water-based solution
- Oil-in-water emulsion
- IV if equipped to deal with over-sedation
Benzodiazepines contraindications
- Elderly: more susceptible to effects so require lower doses
- Respiratory impairment
- Neuromuscular disease e.g. myasthenia grvis
- Liver failure: can cause hepatic encephalopathy - if essential e.g. alcohol withdrawal, choose lorazepam as less liver dependent
Benzodiazepines side effects
- Drowsiness, sedation and coma
- Overdose: cardiorespiratory depression, loss of airway reflexes = airway obstruction and death
- Tolerance
- Abrupt cessation = withdrawal reaction similar to alcohol
Benzodiazepines interactions
- Additive effect to other sedatives e.g. opiates and alcohol
- Use cP450 enzymes so use in addition to inhibitors may increase their effects
Benzodiazepines patient info
- Only short-term measure
- Discuss risks of dependence
- Should not drive or operate machinery after taking
- Sleepiness may persist
Acetylcholinesterase inhibitors examples
Donepezil, galantamine, rivastigmine
Acetylcholinesterase inhibitor indications
- To slow progression of Alzheimer’s disease
Acetylcholinesterase inhibitors MOA
- Inhibits acetylcholinesterase enzyme responsible for the breakdown of acetylcholine in the synaptic cleft
- This leaves more acetylcholine available for cholinergic function
- Effects may lessen as disease course progresses as fewer neurones remain functionally intact
Acetylcholinesterase inhibitors administration
Oral, 5mg increase to 10mg
Acetylcholinesterase inhibitors contraindications
Use with caution in:
- asthma
- COPD
- sick sinus syndrome
- supra-ventricular conduction abnormalities
- increased risk of peptic ulcers
Acetylcholinesterase inhibitors side effects
- Nausea
- Vomiting and diarrhoea
- Difficulty sleeping
- Muscle cramps
- Decreased appetite
Acetlycholinesterase inhibitors patient information
Take at bedtime
