T Pawełczyk and I Kłoszewska,
Przeglad lekarski, 2008
Clinicians perceive psycho-farmacotherapy as a real challenge mainly because of numerous adverse effects and drug interacions that may lead to potential life threatening consequences. The amount information that must be taken into account while prescribing psychotropic drugs grows day by day and it is really difficult to stay well informed. Food, like grapefruit juice (GJ), is also a significant source of interactions, which is sometimes forgotten. Grapefruit contains active bioflavonoids that may change bioavailability of many medications and raise its concentrations above toxic levels. The mechanism of interaction is complex and connected with the influence of GJ active ingredients on prehepatic metabolism and enteric absorption pathways using p-glicoprotein (PGP) and organic anion transporting polipeptide (OATP). The main direction of GJ action is inhibition of cytochrome P450 1A2 and 3A4 isoforms. A wide range of medicines used in daily psychiatric practice undergoes phase I oxidation with CYP 3A4 and 1A2 i.e.: anxiolytics, antidepressants, mood stabilizers, antipsychotics and procognitive compounds. It raises the potential risk of dangerous interactions with grapefruit juice. GJ is generally contraindicated to patients taking psychotropics and it is advised to inform patients about described interaction.