Ciprofloxacin clozapine, interaction

A possible pharmacokinetic interaction between ciprofloxacin, which inhibits CYP1A2, and clozapine, with moderately increased serum concentrations of clozapine, has been reported (249). 

An isolated report describes the development of agitation in an elderly man taking clozapine, which was tentatively attributed to an interaction with ciprofloxacin. A study supports this observation. 

This appears to be an isolated case but it is consistent with the way rifampicin interacts with other drugs. Clozapine serum levels should be well monitored if rifampicin is added, being alert for the need to increase its dosage. An alternative (as in this case) is to use another antibacterial. However, note that there are reports of an interaction between clozapine and ciprofloxacin , (p.749). 

Drug-drug interactions A case series of four patients reported elevation in clozapine serum levels with the coadministration of perazine, possibly through the inhibition of CYP1A2 [137 ]. Self-medication with St John s wort Hypericum perforatum), an inducer of CYP1A2, led to a reduction in clozapine levels and decompensation in a stable patient [138 ]. An increase in clozapine concentration is reported in a patient being treated for an infection with ciprofloxacin [139 ]. Pregabalin-associated increase of clozapine levels has been described [140 ]. 

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