Distinguishing between clinical features of a medication discontinuation syndrome, adverse events, depression symptoms (or exacerbation) and a serotonin syndrome |
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| Discontinuation | Adverse events | Depression | Serotonin syndrome |
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Clinical features | Dizziness, nausea, anxiety, headache (most commonly reported symptoms) | Asthenia, diarrhoea, nausea, anxiety, dizziness, insomnia, nervousness, somnolence, tremor (most common symptoms) | Depression and lack of interest predominate, but can have prominent anxiety and sleep disorder | Abdominal cramps, diarrhoea, tremulousness, myoclonus, coma, tachycardia, hypo- or hypertension, confusion, disorientation, diaphoresis, hyperpyrexia, etc. |
Context |
- Rapid reduction or stopping of SSRIs
- Check if patient has altered dose, `forgotten' tablets, or `run out'
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- Mostly in the first 1-2 weeks of treatment
- Mostly settle if medication is continued
- Check not a drug interaction, especially SSRI with TCA; stop concurrent TCA
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- Continuation or worsening of initial illness
- About 10-20% of patients relapse with continued treatment; some improve with an increased dose, others need change of medication
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- Over dosage
- Drug interaction (especially SSRI + MAOI, or SSRI + TCA)
- Inadequate drug free interval in changing medications
- Idiosyncratic reaction
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Response to increased SSRI dose | Usually relieved | Usually worsens | No acute change, except possible adverse event | Worsens - could be dangerous |
Response to decreased SSRI dose | Usually worsens | Usually relieved | No acute change, or subsequent worsening with relapse, or discontinuation syndrome | Usually relieved if SSRI ceased, and ceasing interacting medicines if possible |
Symptoms persist despite intervention | Seek a psychiatric second opinion | Seek a psychiatric second opinion | Seek a psychiatric second opinion | Emergency, seek immediate second opinion, possibly hospitalise |
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Note: There may be overlap between these conditions and the differentiation may be clinically difficult. SSRI - selective serotonin reuptake inhibitor TCA - tricyclic antidepressant MAOI - irreversible non-selective inhibitors of monoamine oxidases A and B |