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Table 8: Antidepressant-free intervals recommended when changing from one antidepressant to another.¹¹ (Normal version here)

		citalopram paroxetine	fluoxetine	moclobemide	venlafaxine	TCAs	tranylcypromine phenelzine
	citalopram paroxetine	nil	nil	2 to 4 daysa	2 to 4 days	2 to 4 daysc	1 week
	fluoxetined	1 week	-	1 week	1 week	2 weeksc	5 weeks
	moclobemidea (if moderate or lower doses of both drugs)	1 to 2 days	1 to 2 days	-	1 to 2 days	1 to 2 days	nil
	venlafaxine	1 to 2 days	1 to 2 days	1 to 2 days	-	1 to 2 days	1 week
	TCAs	2 to 4 days	2 to 4 days	2 to 4 dayse (1 week for clomipramine)	2 to 4 days	nil	1 week
	tranylcypromineb phenelzineb	2 weeks	2 weeks	Nil (for moderate or low doses of both drugs)	2 weeks	2 weeks	2 weeks
Notes The risk of adverse effects needs to be weighed against the risk of undue delay in response to treatment. Monitor closely to detect adverse effects, particularly serotonin toxicity Nil = start the new drug on the next day If changing from the short acting SSRIs (citalopram, paroxetine) moclobemide dose should be held at 300 mg/day for the first week. Dose may be subsequently increased if necessary. This recommendation is only for changing from low or moderate doses of SSRIs. High doses of SSRIs should be gradually reduced and then stopped before starting moclobemide. Irreversible nonselective MAOIs (phenelzine, tranylcypromine) should be commenced with caution after all other antidepressants because of the risk of severe hypertension, stroke and serotonin toxicity. Allowance should be made for the washout period. When changing from an SSRI to a TCA, the TCA concentration may be elevated for at least several weeks due to persisting SSRI-induced cytochrome P450 inhibition. Care is required when changing from fluoxetine to another antidepressant as it has a longer half-life than other SSRIs, leading to meaningful concentrations of fluoxetine or its active metabolite being present for about 5 weeks after cessation. When changing from a TCA to moclobemide, the moclobemide dose should be held at 300 mg/day for the first week. Dose may be subsequently increased if necessary. This recommendation is only for changing from low or moderate doses of TCA (e.g. up to 150 mg imipramine).