increases the exposure to tolvaptan. Avoid.
▶ Grapefruit juice is predicted to increase the exposure to
ulipristal. Avoid if used for uterine fibroids.oTheoretical
▶ Grapefruit juice is predicted to increase the exposure to
venetoclax. Avoid.rTheoretical
GENERAL INFORMATION Desensitising vaccines should be
avoided in patients taking beta-blockers (adrenaline might be
ineffective in case of a hypersensitivity reaction) or ACE
inhibitors (risk of severe anaphylactoid reactions).
▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,
phenytoin, primidone) are predicted to decrease the exposure
▶ Antifungals, azoles (itraconazole, ketoconazole, voriconazole) are
predicted to moderately to markedly increase the exposure to
▶ Bosentan is predicted to markedly decrease the exposure to
▶ Grazoprevir is predicted to increase the concentration of
calcium channel blockers.oTheoretical
▶ Ciclosporin greatly increases the exposure to grazoprevir.
▶ Cobicistat is predicted to moderately to markedly increase the
exposure to grazoprevir. Avoid.rStudy
▶ Efavirenz is predicted to markedly decrease the exposure to
▶ Elvitegravir markedly increases the exposure to grazoprevir.
▶ Enzalutamide is predicted to decrease the exposure to
▶ Etravirine is predicted to decrease the exposure to grazoprevir.
▶ HIV-protease inhibitors are predicted to moderately to
markedly increase the exposure to
▶ Idelalisib is predicted to moderately to markedly increase the
exposure to grazoprevir. Avoid.rStudy
▶ Macrolides (clarithromycin) are predicted to moderately to
markedly increase the exposure to
▶ Mitotane is predicted to decrease the exposure to grazoprevir.
▶ Modafinil is predicted to decrease the exposure to grazoprevir.
▶ Nevirapine is predicted to markedly decrease the exposure to
▶ Rifampicin is predicted to decrease the exposure to
▶ St John’s Wort is predicted to markedly decrease the exposure
▶ Grazoprevir increases the exposure to statins (atorvastatin).
Adjust atorvastatin dose, p. 202.oStudy
▶ Grazoprevir is predicted to increase the exposure to statins
(fluvastatin). Adjust fluvastatin dose, p. 203.qTheoretical
▶ Grazoprevir increases the exposure to statins (rosuvastatin).
Adjust rosuvastatin dose, p. 204.oStudy
▶ Grazoprevir is predicted to increase the exposure to statins
. Adjust simvastatin dose, p. 205.q ▶ Grazoprevir is predicted to increase the concentration of
. Use with caution and adjust dose.o ▶ Grazoprevir
increases the exposure to tacrolimus.o
ROUTE-SPECIFIC INFORMATION Interactions do not generally
apply to topical use unless specified.
▶ Alcohol (beverage) potentially causes a disulfiram-like
reaction when given with griseofulvin.oAnecdotal
▶ Antiepileptics (phenobarbital, primidone) decrease the effects of
▶ Griseofulvin potentially decreases the efficacy of combined
hormonal contraceptives. For FSRH guidance, see
Contraceptives, interactions p. 794.rAnecdotal
▶ Griseofulvin potentially decreases the anticoagulant effect of
▶ Griseofulvin potentially decreases the efficacy of desogestrel.
Contraceptives, interactions p. 794.
▶ Griseofulvin decreases the efficacy of etonogestrel. For FSRH
Contraceptives, interactions p. 794.r
▶ Griseofulvin potentially decreases the efficacy of oral
levonorgestrel. For FSRH guidance, see Contraceptives,
interactions p. 794.rAnecdotal
▶ Griseofulvin potentially decreases the efficacy of
norethisterone. For FSRH guidance, see Contraceptives,
interactions p. 794.rAnecdotal
▶ Griseofulvin potentially decreases the efficacy of ulipristal. For
Contraceptives, interactions p. 794.r
Guanethidine → see TABLE 8 p. 1376 (hypotension)
▶ Amfetamines (dexamfetamine) decrease the effects of
is predicted to decrease the effects of guanethidine.
Theoretical → Also see TABLE 8 p. 1376
▶ Droperidol is predicted to decrease the effects of guanethidine.
Monitor and adjust dose.oTheoretical → Also see TABLE 8
▶ Haloperidol is predicted to decrease the antihypertensive
o ▶ Monoamine-oxidase A and B inhibitors, irreversible are
predicted to decrease the antihypertensive effects of
. Avoid and for 14 days after stopping the MAOI.
Theoretical → Also see TABLE 8 p. 1376
▶ Phenothiazines are predicted to decrease the antihypertensive
effects of guanethidine.oTheoretical → Also see TABLE 8
▶ Guanethidine is predicted to increase the effects of
sympathomimetics, inotropic (dopamine).rTheoretical
▶ Guanethidine is predicted to increase the effects of
sympathomimetics, vasoconstrictor (adrenaline/epinephrine,
noradrenaline/norepinephrine).oStudy
▶ Guanethidine increases the effects of sympathomimetics,
vasoconstrictor (metaraminol).rAnecdotal
▶ Guanethidine increases the effects of sympathomimetics,
vasoconstrictor (phenylephrine).rStudy
▶ Tricyclic antidepressants are predicted to decrease the
antihypertensive effects of guanethidine.oStudy → Also
BNF 78 Grapefruit juice — Guanethidine 1461
Guanfacine → see TABLE 8 p. 1376 (hypotension), TABLE 11 p. 1377 (CNS
▶ Antiarrhythmics (dronedarone) are predicted to increase the
guanfacine. Adjust guanfacine dose, p. 352.
▶ Antiepileptics (carbamazepine, fosphenytoin, phenobarbital,
phenytoin, primidone) are predicted to decrease the
guanfacine. Adjust guanfacine dose, p. 352.
Study → Also see TABLE 11 p. 1377
▶ Antiepileptics (oxcarbazepine) are predicted to decrease the
concentration of guanfacine. Monitor and adjust guanfacine
▶ Guanfacine increases the concentration of antiepileptics
(valproate). Monitor and adjust dose.oStudy
▶ Antifungals, azoles (fluconazole, isavuconazole, posaconazole)
are predicted to increase the concentration of guanfacine.
Adjust guanfacine dose, p. 352.oTheoretical
▶ Antifungals, azoles (itraconazole, ketoconazole, voriconazole) are
predicted to increase the exposure to guanfacine. Adjust
guanfacine dose, p. 352.oStudy
▶ Aprepitant is predicted to increase the concentration of
guanfacine. Adjust guanfacine dose, p. 352.oTheoretical
▶ Bosentan is predicted to decrease the concentration of
guanfacine. Adjust dose.oTheoretical
▶ Calcium channel blockers (diltiazem, verapamil) are predicted to
increase the concentration of guanfacine. Adjust guanfacine
dose, p. 352.oTheoretical → Also see TABLE 8 p. 1376
▶ Chloramphenicol is predicted to increase the exposure to
guanfacine. Adjust guanfacine dose, p. 352.oTheoretical
▶ Cobicistat is predicted to increase the exposure to guanfacine.
Adjust guanfacine dose, p. 352.oStudy
▶ Crizotinib is predicted to increase the concentration of
guanfacine. Adjust guanfacine dose, p. 352.oTheoretical
▶ Efavirenz is predicted to decrease the concentration of
guanfacine. Adjust dose.oTheoretical
▶ Enzalutamide is predicted to decrease the concentration of
guanfacine. Adjust guanfacine dose, p. 352.oStudy
▶ Fosaprepitant is predicted to increase the concentration of
▶ Grapefruit juice is predicted to increase the exposure to
guanfacine. Avoid.oTheoretical
▶ HIV-protease inhibitors are predicted to increase the exposure
to guanfacine. Adjust guanfacine dose, p. 352.oStudy
▶ Idelalisib is predicted to increase the exposure to guanfacine.
Adjust guanfacine dose, p. 352.oStudy
▶ Imatinib is predicted to increase the concentration of
guanfacine. Adjust guanfacine dose, p. 352.oTheoretical
▶ Macrolides (clarithromycin) are predicted to increase the
guanfacine. Adjust guanfacine dose, p. 352.
▶ Macrolides (erythromycin) are predicted to increase the
concentration of guanfacine. Adjust guanfacine dose, p. 352.
▶ Guanfacine is predicted to increase the concentration of
▶ Mitotane is predicted to decrease the concentration of
guanfacine. Adjust guanfacine dose, p. 352.oStudy
▶ Netupitant is predicted to increase the concentration of
guanfacine. Adjust guanfacine dose, p. 352.oTheoretical
▶ Nevirapine is predicted to decrease the concentration of
guanfacine. Adjust dose.oTheoretical
▶ Nilotinib is predicted to increase the concentration of
guanfacine. Adjust guanfacine dose, p. 352.oTheoretical
▶ Rifampicin is predicted to decrease the concentration of
guanfacine. Adjust guanfacine dose, p. 352.oStudy
▶ St John’s Wort is predicted to decrease the concentration of
guanfacine. Adjust dose.oTheoretical
Guselkumab → see monoclonal antibodies
cimetidine . famotidine . nizatidine .ranitidine. ▶ Cimetidine
decreases the clearance of albendazole.o ▶ Cimetidine increases the concentration of aminophylline.
▶ Cimetidine slightly increases the exposure to anthracyclines
▶ Cimetidine increases the exposure to antiarrhythmics
▶ Cimetidine slightly increases the exposure to antiarrhythmics
(flecainide). Monitor and adjust dose.nStudy
▶ Cimetidine increases the exposure to antiarrhythmics
(lidocaine). Monitor and adjust dose.oStudy
▶ Cimetidine is predicted to increase the exposure to
(propafenone). Monitor and adjust dose.
▶ Cimetidine transiently increases the concentration of
antiepileptics (carbamazepine). Monitor concentration and
▶ Cimetidine increases the concentration of antiepileptics
(fosphenytoin, phenytoin). Monitor concentration and adjust
▶ H2 receptor antagonists are predicted to decrease the
absorption of antifungals, azoles (itraconazole). Administer
itraconazole capsules with an acidic beverage.oStudy
▶ H2 receptor antagonists are predicted to decrease the
absorption of antifungals, azoles (ketoconazole). Administer
ketoconazole with an acidic beverage.oStudy
▶ H2 receptor antagonists are predicted to decrease the exposure
to antifungals, azoles (posaconazole). Avoid use of posaconazole
▶ Cimetidine decreases the clearance of antimalarials
▶ Cimetidine slightly increases the exposure to antimalarials
▶ H2 receptor antagonists are predicted to decrease the
absorption of bosutinib.oTheoretical
▶ Cimetidine slightly increases the exposure to calcium channel
(diltiazem, nimodipine). Monitor and adjust dose.
▶ Cimetidine (high-dose) is predicted to increase the exposure to
calcium channel blockers (lercanidipine).oTheoretical
▶ Cimetidine moderately increases the exposure to calcium
(nifedipine). Monitor and adjust dose.r
▶ Cimetidine increases the exposure to calcium channel blockers
▶ Cimetidine is predicted to slightly increase the exposure to
▶ H2 receptor antagonists are predicted to decrease the
absorption of ceritinib.oTheoretical
▶ Cimetidine increases the concentration of ciclosporin.n
increases the anticoagulant effect of coumarins.
▶ H2 receptor antagonists are predicted to decrease the exposure
▶ H2 receptor antagonists are predicted to decrease the
dipyridamole (immediate release tablets).
▶ Cimetidine is predicted to increase the exposure to dopamine
receptor agonists (pramipexole). Adjust dose.oStudy
▶ H2 receptor antagonists are predicted to decrease the exposure
to erlotinib. Erlotinib should be taken 2 hours before or
10 hours after H2 receptor antagonists.oStudy
increases the concentration of fampridine. Avoid.
slightly increases the exposure to fluorouracil.
▶ H2 receptor antagonists are predicted to slightly to moderately
decrease the exposure to gefitinib.oStudy
▶ H2 receptor antagonists decrease the exposure to HIV-protease
inhibitors (atazanavir). Monitor and adjust dose.oStudy
▶ Cimetidine is predicted to decrease the clearance of
hydroxychloroquine.oTheoretical
▶ H2 receptor antagonists are predicted to decrease the
absorption of lapatinib. Avoid.oTheoretical
▶ H2 receptor antagonists are predicted to decrease the exposure
ledipasvir. Adjust dose, see ledipasvir with sofosbuvir p. 628.
1462 Guanfacine — H2 receptor antagonists BNF 78
▶ Leflunomide is predicted to increase the exposure to H2
(cimetidine, famotidine).o ▶ H2 receptor antagonists (cimetidine, ranitidine) are predicted to
increase the exposure to lomitapide. Separate administration
▶ Cimetidine slightly increases the exposure to macrolides
increases the concentration of mebendazole.
▶ Cimetidine increases the exposure to metformin. Monitor and
▶ Cimetidine slightly increases the exposure to mirtazapine. Use
with caution and adjust dose.oTheoretical
▶ Cimetidine increases the exposure to moclobemide. Adjust
moclobemide dose, p. 362.nStudy
▶ H2 receptor antagonists are predicted to decrease the
absorption of nilotinib. H2 receptor antagonists should be taken
10 hours before or 2 hours after nilotinib.nTheoretical
▶ Cimetidine increases the concentration of opioids (alfentanil).
Use with caution and adjust dose.rStudy
increases the exposure to opioids (fentanyl).
▶ H2 receptor antagonists are predicted to decrease the exposure
to pazopanib. H2 receptor antagonists should be taken 10 hours
before or 2 hours after pazopanib.oTheoretical
increases the exposure to phenindione.r
moderately increases the exposure to praziquantel.
▶ H2 receptor antagonists are predicted to decrease the exposure
to rilpivirine. H2 receptor antagonists should be taken 12 hours
Comments
Post a Comment
اكتب تعليق حول الموضوع