1. GRAPEFRUI TS The King’s School MedSoc 2014-2015

3. The science behind what the says Grapefruit contains a class of chemicals called furanocoumarins. Furanocoumarins inhibit an enzyme, cytochrome P450 3A4, that is responsible for the inactivation of approximately half of all drugs. Angelicin (a furanocoumarin)

4. The enzyme is found in the lining of the gut and in the liver. Furanocoumarins in grapefruit mainly inhibit cytochrome P450 3A4 in the gut. This means that if a drug that is normally broken down by cytochrome P450 3A4 is taken at the same time as grapefruit, more ‘active’ drug will be absorbed by the body, as less will have been inactivated by the enzyme. The prescribed dose of these drugs takes into account the fact that some of the drug will be inactivated by P450 3A4. So if this doesn’t occur, it leads to the person being exposed to higher concentrations of the drug than was intended, and this can have adverse effects. The science behind what the says

5. What drugs are affected by grapefruit? Drugs used to treat cancer (crizotinib, dasatinib, erlotinib,everolimus, lapatinib, nilotinib, pazopanib, sunitinib, vandetanib, vemurafenib) Drugs used to treat or prevent infections (erythromycin, halofantrine, maraviroc, primaquine, quinine, rilpivirine) Drugs used to treat high cholesterol (atorvastatin, lovastatin, simvastatin) Drugs used to treat heart and blood vessel conditions(amiodarone, apixaban, clopidogrel, dronedarone, eplerenone, felodipine, nifedipine, quinidine, rivaroxaban, ticagrelor) Drugs affecting the central nervous system (oral alfentanil, buspirone, dextromethorphan, oral fentanyl, oral ketamine, lurasidone, oxycodone, pimozide, quetiapine, triazolam, ziprasidone) Drugs used to treat nausea (domperidone) Immunosuppressants (cyclosporine, everolimus, sirolimus, tacrolimus) Drugs used to treat urinary tract conditions(darifenacin, fesoterodine, solifenain, silodosin, tamsulosin)

6. Some of the side effects Torsade de pointes Complete heart block Rhabdomyolysis Nephrotoxicity Myelotoxicity Venous thrombosis

7. Thank you for watching Source: NHS Choices, not the Daily Mail