Psychiatry pharmacology Flashcards
HYPNOTICS - Z DRUGS
Name 2 examples
zopiclone
zolpidem
HYPNOTICS - Z DRUGS
What are the indications and the MOA of these drugs
Short term tx of insomnia that is distressing - Max 4 weeks
Facilitate and enhance binding of GABA to GABA receptor - GABA agonist
Opens chloride channels making cells more resisitant to depolarisation
Similar effect to BDZs but different strucutually - Act on alpha-2 subunit of the receptor
HYPNOTICS - Z DRUGS
What are the adverse effects and cations for these drugs
daytiem sleepiness rebound insomnia headache confusion nightmares
Elderly - increased risk of falls
Don’t drive
Don’t operate complex/heavy machinery
BENZODIAZEPINES
What is the MOA?
Enhance effect of inhibitory GABA by increasing frequency of Cl- channels + flow of Cl- ions causing hyperpolarisation of membrane + so prevention of further excitation
BENZODIAZEPINES
Wha are some inidcations for BDZs use?
Anticonvulsant - seizures Alcohol withdrawal sedation axiolytic muscle relaxant
BENZODIAZEPINES
What are some adverse effects of BDZs?
Dose dependant drowsiness
tolerance
confusion
dizziness
Monitor fro resp depression
BENZODIAZEPINES
Name some examples and how long should they be prescribed for?
Diazepam - longer duration
Lorazepam
Temazepam - shorter duration
Chlordiazepoxide
2-4 weeks due to risks of tolerance and dependence
BENZODIAZEPINES
What drugs can BDZs interact with?
Anti-hypertensives - Enhanced hypotensive effects
BENZODIAZEPINES
How do you manage a BDZ overdose?
What is the risk of this?
IV Flumazenil
Danger of inducing status epilpeticus or death
BENZODIAZEPINES
What is BDZs withdrawal syndrome, how does it occur and present?
BDZs withdrawa too quickly
Occurs 3 weeks after stopping long-acting drug
Insomnia irritability anxiety tremor loss of appetite seizures perspiration
BENZODIAZEPINES
What are some cautions for BDZs usage?
Elderly - Increased falls risk
Patients with liver disease - Risk of precipitating HE
ANTI-DEPRESSANTS
What moniroing is required for patinets starting on anti-depressants?
When can an anti-depressant be stopped?
Monitored twice weekly to ensure dose is working and patient is stable
Weekly if <30 due to increased suicide risk
Carried on for 6m followinf sx resolution to reduce risk of relapse
ANTI-DEPRESSANTS
How should anti-depressants be stopped?
Gradual dose reduction over 4 weeks
Suddenly stopping can cause withdrawal effects: Rebound depression pain diarrhoea vomiting sweating restlesness
ANTI-DEPRESSANTS
What is the MOA for SSRIs?
Preferentially inhibit neuronal reuptak eof serotonin from synaptic cleft by inhibiting reuptake transporter on th epost synaptic membrane
ANTI-DEPRESSANTS
Name some examples of SSRIs?
sertraline citalopram fluoxetine Paroxetine citalopram
ANTI-DEPRESSANTS
Name some adverse effects of SSRIs
8 S' Size - weight gain Sick - nausea / vomiting Serotonin syndrome Seizure - Lower threshold Stomach upset - abdo pain / constipation / diarrhoea Stress - anxiety Suicidal thoughts Sexual difficulty - Impotence Sleep difficulty Sodium low - Hyponatraemia
ANTI-DEPRESSANTS
What is one important adverse effect of citalopram?
Prolongs QTc interval - Dose dependent
ANTI-DEPRESSANTS
What are some cautions for SSRIs?
Increase in suicidal thoughts
May precipitate manic phase in bipolar
Epilpesy patients
Patients wit PUD
ANTI-DEPRESSANTS
What are the risks of SSRIs in preganncy?
1st trimester - Risk of Congenital heart defects
3rd trimester - Risk of persistent pulmonary HTN of newborn
ANTI-DEPRESSANTS
What is the influence of paroxetine in pregnancy?
Increased risk of congenital malformations - particualry in 1st trimester
ANTI-DEPRESSANTS
Why are SSRIs preffered over TCAs?
Fewer adverse side effects
Less dangerous on overdose
ANTI-DEPRESSANTS
Name some SSRIs interactions
- Warfarin / Heparin
- Triptans (Can cause SS)
- Aspirin + NSAIDs (Add PPI due to risk of GI bleed)
- Antipsychotics (QT prolongation)
- MAOI (Both increase syanptic serotonin levels –>SS) Have to wait 2weeks
ANTI-DEPRESSANTS
What is the mechanism of action of SNRIs?
Give some examples
Prevents reuptake + subsequent degradation of serotonin AND noradrenaline from synaptic cleft by inhibiting reuptake transporters on post-synaptic membrane
- Venlafaxine, duloxetine
ANTI-DEPRESSANTS
Name some adverse effects of SNRIs?
Similar to SSRIs Size - weight gain Sick - nausea / vomiting Serotonin syndrome Seizure - Lower threshold Stomach upset - abdo pain / constipation / diarrhoea Stress - anxiety Suicidal thoughts Sexual difficulty - Impotence Sleep difficulty
ANTI-DEPRESSANTS
What is the mechanism of action of monoamine oxidase inhibitors (MAOI)?
Give some examples.
Inhibits monoamine oxidase enzyme which reduces breakdown of adrenaline, noradrenaline + serotonin so increases level
Isocarboxazid
Phenelzine
Selegiline
ANTI-DEPRESSANTS
What is different about selegiline in comparison to other MAIOs?
Selegiline is selective MAO-B inhibitor which also increases dopamine
ANTI-DEPRESSANTS
What are some adverse effects to MAOIs?
sexual dysfunction hypotension weight gain dry mouth dizziness migraines
ANTI-DEPRESSANTS
What is the link between tyramine and MAOIs?
MAO breaks down tyramine (cheese, cured/smoked meet, alcohol)
MAO-I= increased tyramine
Tyramine mimics noradrenaline= hypertensive crisis
->headache, increased HR, palpitations, chest pain, N/V, anxiety
ANTI-DEPRESSANTS
What foods increase the risk of a hypertensive crisis from MAOIs?
High tyramine foods
- aged cheese
- cured meats
- broad beans
- wine
- marmite
ANTI-DEPRESSANTS
What is the mechanism of action of tricyclic antidepressants (TCAs)?
Give some examples
Inhibit neuronal reuptake of serotonin
(5-HT) and noradrenaline from the synaptic cleft, thereby increasing
their availability for neurotransmission.
Tricyclic antidepressants also block a wide array of receptors,
including muscarinic, histamine (H1), α-adrenergic (α1 and α2) and
dopamine (D2) receptors.
Amitryptiline
Dosilepin
ANTI-DEPRESSANTS
What are the side effects of TCAs?
Anticholinergic - think/see/pee/spit blurred vision urinalry retention constipation dry mouth confusion
Anti-adrenergic
Postural hypotension
impotence
Other Arrthymias Cardiotoxicity seizures weight gain
ANTI-DEPRESSANTS
What cautions are there for TCAs?
Caution in CVD - Avoid following MI
Cardiotoxicity in overdose - caution in suicidal patients
(QTc prolongation)
ANTI-DEPRESSANTS
In terms of TCA overdose…
i) mild-moderate Sx?
ii) severe Sx?
iii) ECG signs?
iv) management?
i) Dilated pupils, dry mouth, urinary retention, increased tendon reflexes + extensor plantars
ii) Fits, coma, cardiac arrhythmias > arrest
iii) Sinus tachy, wide QRS, prolonged QT interval
iv) Sodium bicarbonate
ANTI-DEPRESSANTS
What is the mechanism of action of mirtazapine?
What are some side effects?
Blocks alpha-2 adrenergic receptors > increased release of neurotransmitters
- Increased appetite + weight gain
- Sedation / Drowsy
- increased triglyceride levels
MOOD STABALISERS
Name some examples
Lithium
sodium valporate
Carbamazepine
Lamogitrine
MOOD STABALISERS
What is lithium’s MOA and what is the target range for blood levels?
Lithium inhibits cAMP production which inhibits monamines
Narrow theraputic range (0.4 - 1.0 mmol/L)
MOOD STABALISERS
What are the adverse effects of lithium at a theraputic dose?
fine tremor dry mouth GI disturbance - Increased GI motility Hypothyroidism Increased thirst Increased urination Hypothyroidism Drowsiness weight gain
MOOD STABALISERS
What is the presentation of lithium toxicity?
Tremor (COARSE) Oliguric (renal failure) ataXia Increased reflexes Convulsions - seizures Coma Consciousness reduced
Nausea
muscle weakness
Dysarthria
Nystagmus