Citalopram, escitalopram,
paroxetine and sertraline levels are moderately increased by
cimetidine.
Initial dosage reductions are not needed, but be aware that some patients may have an increase in SSRI adverse effects (dry mouth, nausea, diarrhoea, dyspepsia, tremor, ejaculatory delay, sweating), in which case dose reductions may be appropriate. Although not proven, it is thought that ranitidine and
famotidine are unlikely to interact.