depression Flashcards
How long to continue treatment with an antidepressant before considering a switch?
4 weeks (6 weeks in elderly)
How long should a person be on an antidepressant?
1st episode at least 6 months
12 months in elderly or GAD
2 years if history of recurrent hx
What electrolyte disbalance can occur with all antidepressants and which class in particular?
Hyponatraemia (especially in elderly)
Higher risk in SSRI
Symptoms: Drowsiness, confusion
Serotonin syndrome symptoms
Symptoms - 3 main areas, but
may not be seen in all patients.
1. neuromuscular hyperactivity
(tremor, hyperreflexia, clonus,
myoclonus, rigidity),
2. autonomic dysfunction
(tachycardia, blood pressure
changes, hyperthermia,
diaphoresis, shivering, diarrhoea),
3. altered mental state (agitation,
confusion, mania).
Why does serotonin syndrome occur
Caused by excessive central and peripheral serotonergic activity. Symptoms can occur within hours/days after initiation, dose escalation, overdose or addition of antidepressant/replacement without long enough washout period
Which antidepressants need a long washout period
Irreversible MAOI
Drug with long half lives
Treatment failure in depression
4 weeks
Increase dose/Switch SSRI or mirtazapine
2nd line- Lofepramine, meclobemide and reboxetine
TCA overdose
Symptoms:
Dry mouth, coma, hypotension,
hypothermia, hyperreflexia,
extensor plantar responses,
convulsions, respiratory failure,
cardiac conduction defects,
arrhythmias, dilated pupils, urinary
retention.
Antidote: Activated charcoal, lorazepam, diazepam
SSRI overdose
symptoms: nausea,
vomiting, agitation, tremor,
nystagmus, drowsiness, and sinus
tachycardia; convulsions may
occur. Rarely, severe poisoning
results in serotonin syndrome, with
marked neuropsychiatric effects,
neuromuscular hyperactivity, and
autonomic instability.
Hyperthermia, rhabdomyolysis,
renal failure, and coagulopathies
may develop
Antidote: Activated charcoal, lorazepam, diazepam or midazolam
Withdrawing SNRI
Withdrawal: GI disturbances, headaches, anxiety, dizziness, tremor, sleep disturbances, sweating.
Venlafaxine associated with higher risk. Reduce dose over several weeks
Duloxetine reduce dose over 1-2 weeks
Withdrawing SSRI
Symptoms: GI disturbances, headache, anxiety, dizziness, tinnitus, sweating, fatigue
Reduce dose over several weeks (longer in long term maintenance treatment)
Withdrawing TCA
Symptoms: Agitation, irritability, nausea, sweating, chills, muscle aches, insomnia, lethargy
Reduce dose over 4 weeks or longer if withdrawal symptoms emerge or long term maintenance treatment
MOAI key interaction
Tyramine containing foods
How long to wait after stopping MAOI before starting another antidepressant
At least 2 weeks. Do not start another MAOI until 2 weeks after previous MAOI, 1 week after TCA or SSRI
