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Clinical Handbook of Psychotropic Drugs, 18th Edition, © 2009 Hogrefe & Huber Publishers
Switching Antidepressants
Antidepressant Non-Response
Factors Complicating Response
l
l
l
l
l
l
l
l
Switching Antidepressants
l
l
l
l
Advantages of Switching
l
l
l
Disadvantages of Switching
l
l
l
Switching from
Ascertain diagnosis is correct; ascertain patient is compliant with therapy
Ensure dosage prescribed is therapeutic; measure plasma level; ensure there has been an adequate trial period, i.e., up to 6 weeks at a reasonable
dose
Concurrent medical or psychiatric illness, e.g., hypothyroidism, obsessive compulsive disorder
Concurrent prescription drugs may interfere with efficacy, e.g., calcium channel blockers
Metabolic enhancers (e.g., carbamazepine) or inhibitors (e.g., erythromycin) will affect plasma level of antidepressant
Drug abuse may make management difficult, e.g., cocaine
Psychosocial factors may affect response
Personality disorders lead to poor outcome; however, depression may evoke personality problems which may disappear when the depression is
alleviated
Switching from one SSRI to another can offer enhanced response in previously non-responsive patients
20–25% remission rate when switching from SSRI to another class of antidepressant or a different SSRI after failure of first SSRI (STAR*D studies)
Use caution when switching to or from irreversible MAOIs (see Switching Antidepressants pp. 66–67)
Switching between tricyclic agents is of questionable benefit
Minimizes polypharmacy
Second agent may be better tolerated
Less costly
Time required to taper first agent or need for a washout (risk of relapse)
Lose partial efficacy of first agent
Delayed onset of action
Switching to
Washout Period(a)
Non-selective cyclic
fi
fi
fi
fi
fi
fi
Non-selective Cyclic
SSRI
NDRI
SNRI or SARI, NaSSA
Irrev. MAOI, MAO-B
RIMA
No washout – use dose equivalents for switching (pp. 64–65)
5 half-lives of cyclic antidepressant (caution: see Interactions, p. 10)(b)
5 half-lives of cyclic antidepressant
No washout – taper(b)
5 half-lives of cyclic antidepressant
5 half-lives of cyclic antidepressant
SSRI or SARI
fi
fi
fi
fi
fi
fi
Non-selective Cyclic
NDRI
SNRI
Irrev. MAOI, MAO-B
RIMA
SSRI or SARI, NaSSA
5 half-lives of SSRI or SARI (caution: with fluoxetine due to long half-life of active metabolite)(b)
No washout – taper (caution: with fluoxetine)(b)
No washout – taper (caution: with fluoxetine)(b), monitor for serotonergic effects
5 half-lives of SSRI or SARI (caution: with fluoxetine) – DO NOT COMBINE
5 half-lives of SSRI or SARI (caution: with fluoxetine)
No washout – taper first drug over 2–5 days then start second drug (use lower doses of second drug if switching from fluoxetine; longer
taper may be necessary if higher doses of fluoxetine used); monitor for serotonergic effects
Switching from
Switching to
Washout Period(a)
NDRI
fi
fi
fi
fi
fi
Non-selective Cyclic
SSRI or SARI
SNRI , NaSSA
RIMA
Irrev. MAOI, MAO-B
2 days
No washout – taper (caution with fluoxetine)(b)
No washout – taper(b); monitor for noradrenergic effects
5 half-lives of NDRI (3–5 days) – DO NOT COMBINE
5 half-lives of NDRI (3–5 days) – DO NOT COMBINE
SNRI or NaSSA
fi
fi
fi
fi
fi
fi
Non-selective Cyclic
SSRI or SARI
NDRI
NaSSA, SNRI
Irrev. MAOI, MAO-B
RIMA
No washout – taper(b)
No washout – taper(b); monitor for serotonergic effects
No washout – taper(b); monitor for noradrenergic effects
No washout – taper(b); monitor for serotonergic and noradrenergic effects
5 half-lives of SNRI (3 days) or NaSSA (5–7 days) – DO NOT COMBINE
5 half-lives of SNRI (3 days) or NaSSA (5–7 days) – CAUTION
Irrev. MAOI
fi
fi
fi
fi
fi
fi
fi
Non-selective Cyclic
SSRI or SARI
NDRI
SNRI
NaSSA
RIMA
Irrev. MAOI, MAO-B
10 days – CAUTION
10 days – DO NOT COMBINE
10 days – DO NOT COMBINE
Minimum of 14 days – DO NOT COMBINE. Caution: case reports of serotonin syndrome after 14 days washout
10 days – DO NOT COMBINE
Start the next day if changing from low to moderate dose; taper from a high dose. Maintain dietary restrictions for 10 days
10 days – DO NOT COMBINE
RIMA
fi
fi
fi
fi
fi
fi
Non-selective Cyclic
SSRI, SARI or NaSSA
NDRI
SNRI
Irrev. MAOI
MAO-B
2 days – CAUTION
2 days – CAUTION
2 days – CAUTION
2 days – CAUTION
Can start the following day at a low dose
2 days – CAUTION
MAO-B
fi
fi
fi
fi
fi
fi
Non-selective Cyclic
SSRI or SARI
NDRI
NaSSA, SNRI
Irrev. MAOI
RIMA
5 days – CAUTION
5 days – CAUTION
5 days – CAUTION
5 days – CAUTION
5 days – CAUTION
5 days – CAUTION
(a)
Recommendations pertain to outpatients. More rapid switching may be used in inpatients (except from an irreversible MAOI or RIMA) with proper monitoring of plasma levels and synergistic effects; (b) Taper first drug over 3 to 7 days prior to initiating second
antidepressant; consider starting second drug at a reduced dose.
Clinical Handbook of Psychotropic Drugs, 18th Edition, © 2009 Hogrefe & Huber Publishers
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Antidepressants