Fosaprepitant(continued)
▶Cobicistatis predicted to increase the exposure to
fosaprepitant.oTheoretical
▶Fosaprepitantis predicted to decrease the efficacy ofcombined
hormonal contraceptives. For FSRH guidance, see
Contraceptives, interactionsp. 497.rStudy
▶Fosaprepitantis predicted to increase the exposure to
corticosteroids(dexamethasone, methylprednisolone). Monitor
and adjust dose.oTheoretical
▶Fosaprepitantis predicted to decrease the anticoagulant effect
ofcoumarins.oTheoretical
▶Fosaprepitantis predicted to decrease the efficacy of
desogestrel. For FSRH guidance, seeContraceptives,
interactionsp. 497.rTheoretical
▶Enzalutamideis predicted to decrease the exposure to
fosaprepitant. Avoid.oTheoretical
▶Fosaprepitantis predicted to decrease the efficacy of
etonogestrel. For FSRH guidance, seeContraceptives,
interactionsp. 497.rTheoretical
▶Fosaprepitantis predicted to increase the concentration of
guanfacine.oTheoretical
▶HIV-protease inhibitorsare predicted to increase the exposure
tofosaprepitant.oTheoretical
▶Fosaprepitantis predicted to decrease the effects ofhormone
replacement therapy.oAnecdotal
▶Fosaprepitantis predicted to slightly increase the exposure to
ibrutinib.oTheoretical
▶Idelalisibis predicted to increase the exposure to
fosaprepitant.oTheoretical
▶Fosaprepitantis predicted to decrease the efficacy of
levonorgestrel. For FSRH guidance, seeContraceptives,
interactionsp. 497.rTheoretical
▶Fosaprepitantis predicted to increase the exposure to
lomitapide. Separate administration by 12 hours.o
Theoretical
▶Macrolides(clarithromycin)are predicted to increase the
exposure tofosaprepitant.oTheoretical
▶Fosaprepitantslightly increases the exposure tomidazolam.
oStudy
▶Mitotaneis predicted to decrease the exposure to
fosaprepitant. Avoid.oTheoretical
▶Fosaprepitantis predicted to decrease the efficacy of
norethisterone. For FSRH guidance, seeContraceptives,
interactionsp. 497.rAnecdotal
▶Fosaprepitantis predicted to increase the exposure to
pimozide. Avoid.rTheoretical
▶Rifampicinis predicted to decrease the exposure to
fosaprepitant. Avoid.oTheoretical
▶St John’s Wortis predicted to decrease the exposure to
fosaprepitant. Avoid.oTheoretical
▶Fosaprepitantdecreases the efficacy ofulipristal. For FSRH
guidance, seeContraceptives, interactionsp. 497.r
Anecdotal
Foscarnet→seeTABLE 2p. 847 (nephrotoxicity)
▶Foscarnetincreases the risk of hypocalcaemia when given with
pentamidine.rAnecdotal→Also seeTABLE 2p. 847
Fosinopril→see ACE inhibitors
Fosphenytoin→see antiepileptics
Frovatriptan→seeTABLE 13p. 850 (serotonin syndrome)
▶SSRIs(fluvoxamine)increase the concentration offrovatriptan.
rStudy→Also seeTABLE 13p. 850
Fulvestrant→seeTABLE 5p. 847 (thromboembolism)
Furosemide→see loop diuretics
Fusidic acid
▶Fusidic acidincreases the risk of rhabdomyolysis when given
withstatins. Avoid.rAnecdotal
Gabapentin→see antiepileptics
Galantamine→see anticholinesterases, centrally acting
Ganciclovir→seeTABLE 15p. 850 (myelosuppression),TABLE 2p. 847
(nephrotoxicity)
ROUTE-SPECIFIC INFORMATIONSince systemic absorption can
follow topical application, the possibility of interactions
should be borne in mind.
▶Gancicloviris predicted to increase the risk of seizures when
given withcarbapenems(imipenem). Avoid.rAnecdotal▶Gancicloviris predicted to increase the exposure todidanosine.
oStudy
▶Mycophenolateis predicted to increase the risk of
haematological toxicity when given withganciclovir.o
Theoretical→Also seeTABLE 15p. 850
Gefitinib→seeTABLE 15p. 850 (myelosuppression)
▶Antacidsare predicted to slightly decrease the exposure to
gefitinib.oTheoretical
▶Antiarrhythmics(dronedarone)are predicted to increase the
exposure togefitinib.oTheoretical
▶Antiepileptics(carbamazepine, fosphenytoin, phenobarbital,
phenytoin, primidone)are predicted to decrease the exposure
togefitinib. Avoid.rStudy
▶Antifungals, azoles(fluconazole, isavuconazole, posaconazole)
are predicted to increase the exposure togefitinib.o
Theoretical
▶Antifungals, azoles(itraconazole, ketoconazole, voriconazole)are
predicted to increase the exposure togefitinib.oStudy
▶Aprepitantis predicted to increase the exposure togefitinib.
oTheoretical
▶Bosentanis predicted to decrease the exposure togefitinib.
Avoid.rTheoretical
▶Calcium channel blockers(diltiazem, verapamil)are predicted to
increase the exposure togefitinib.oTheoretical
▶Cobicistatis predicted to increase the exposure togefitinib.
oStudy
▶Gefitinibis predicted to increase the anticoagulant effect of
coumarins.rAnecdotal
▶Crizotinibis predicted to increase the exposure togefitinib.
oTheoretical→Also seeTABLE 15p. 850
▶Efavirenzis predicted to decrease the exposure togefitinib.
Avoid.rTheoretical
▶Enzalutamideis predicted to decrease the exposure to
gefitinib. Avoid.rStudy
▶H 2 receptor antagonistsare predicted to slightly to moderately
decrease the exposure togefitinib.oStudy
▶HIV-protease inhibitorsare predicted to increase the exposure
togefitinib.oStudy
▶Idelalisibis predicted to increase the exposure togefitinib.
oStudy→Also seeTABLE 15p. 850
▶Imatinibis predicted to increase the exposure togefitinib.
oTheoretical→Also seeTABLE 15p. 850
▶Macrolides(clarithromycin)are predicted to increase the
exposure togefitinib.oStudy
▶Macrolides(erythromycin)are predicted to increase the
exposure togefitinib.oTheoretical
▶Mitotaneis predicted to decrease the exposure togefitinib.
Avoid.rStudy→Also seeTABLE 15p. 850
▶Netupitantis predicted to increase the exposure togefitinib.
oTheoretical
▶Nevirapineis predicted to decrease the exposure togefitinib.
Avoid.rTheoretical
▶Nilotinibis predicted to increase the exposure togefitinib.
oTheoretical→Also seeTABLE 15p. 850
▶Gefitinibis predicted to increase the risk of bleeding events
when given withphenindione.rTheoretical
▶Proton pump inhibitorsare predicted to decrease the exposure
togefitinib.rTheoretical
▶Rifampicinis predicted to decrease the exposure togefitinib.
Avoid.rStudy
▶St John’s Wortis predicted to decrease the exposure to
gefitinib. Avoid.rTheoretical
Gemcitabine→seeTABLE 15p. 850 (myelosuppression)
▶Live vaccinesare predicted to increase the risk of generalised
infection (possibly life-threatening) when given with
gemcitabine. Public Health England advises avoid (refer to
Green Book).rTheoretical
Gemfibrozil→see fibrates
Gentamicin→see aminoglycosides
Glecaprevir
▶Antiarrhythmics(dronedarone)potentially increase the
exposure toglecaprevir.oTheoretical
▶Antiepileptics(carbamazepine, fosphenytoin, phenobarbital,
phenytoin, primidone)are predicted to moderately decrease
the exposure toglecaprevir. Avoid.rStudy924 Fosaprepitant—Glecaprevir BNFC 2018 – 2019
Interactions|Appendix 1A1