An isolated report describes the development of agitation in an elderly man taking
clozapine, tentatively attributed to elevated
serum levels caused by an interaction with ciprofloxacin. A study supports this observation. Ciprofloxacin may inhibit olanza- pine
metabolism, which may result in increased adverse effects. Additive QT- prolonging effects are possible with
gatifloxacin,
levofloxacin, moxifloxacin, and particularly sparfloxacin, and with the antipsychotics, see drugs that prolong the QT interval.
Monitor the outcome of concurrent use closely for
clozapine adverse effects. The manufacturers of
olanzapine recommend a reduced dose. Other
quinolones may also interact, see
quinolones.