▶Clarithromycinis predicted to increase the exposure to
venetoclax. Avoid potent inhibitors of CYP3A4 or adjust
venetoclaxdose.rStudy
▶Erythromycinis predicted to increase the exposure to
venetoclax. Avoid moderate inhibitors of CYP3A4 or adjust
venetoclaxdose.rStudy
▶Clarithromycinis predicted to increase the exposure to
venlafaxine.oStudy→Also seeTABLE 9p. 849
▶Macrolides(clarithromycin, erythromycin)are predicted to
increase the exposure tovinca alkaloids.rTheoretical→
Also seeTABLE 9p. 849
▶Clarithromycinis predicted to increase the exposure tovitamin
D substances(paricalcitol).oStudy
▶Clarithromycindecreases the absorption ofzidovudine.
Separate administration by at least 2 hours.oStudy
▶Clarithromycinis predicted to increase the exposure to
zopiclone. Adjust dose.oTheoretical
▶Erythromycinis predicted to increase the exposure to
zopiclone. Adjust dose.oStudy
Magnesium
▶Oralmagnesiumdecreases the absorption ofbisphosphonates
(alendronic acid).Alendronic acidshould be taken at least
30 minutes beforemagnesium.oStudy
▶Oralmagnesiumis predicted to decrease the absorption of oral
bisphosphonates(ibandronic acid). Avoidmagnesiumfor at least
6 hours before or 1 hour afteribandronic acid.o
Theoretical
▶Oralmagnesiumdecreases the absorption ofbisphosphonates
(risedronate). Separate administration by at least 2 hours.
oStudy
▶Oralmagnesiumdecreases the absorption ofbisphosphonates
(sodium clodronate). Avoidmagnesiumfor 2 hours before or
1 hour aftersodium clodronate.oStudy
▶Intravenousmagnesiumpotentially increases the risk of
hypotension when given withcalcium channel blockers
(amlodipine, clevidipine, felodipine, lacidipine, lercanidipine,
nicardipine, nifedipine, nimodipine, verapamil)(in pregnant
women).rAnecdotal
▶Intravenousmagnesiumincreases the effects ofneuromuscular
blocking drugs, non-depolarising.oStudy
▶Intravenousmagnesiumis predicted to increase the effects of
suxamethonium.oStudy
Magnesium carbonate→see antacids
Magnesium trisilicate→see antacids
Maraviroc
▶Antiepileptics(carbamazepine, fosphenytoin, phenobarbital,
phenytoin, primidone)are predicted to decrease the exposure
tomaraviroc. Adjust dose.rStudy
▶Antifungals, azoles(itraconazole, ketoconazole, voriconazole)are
predicted to markedly increase the exposure tomaraviroc.
Adjust dose.rStudy
▶Bosentanis predicted to decrease the exposure tomaraviroc.
Avoid.oTheoretical
▶Cobicistatmarkedly increases the exposure tomaraviroc. Refer
to specialist literature.rStudy
▶Efavirenzdecreases the exposure tomaraviroc. Refer to
specialist literature.rTheoretical
▶Enzalutamideis predicted to decrease the exposure to
maraviroc. Adjust dose.rStudy
▶Etravirine(with a boosted protease inhibitor) increases the
exposure tomaraviroc. Avoid or adjust dose.oStudy
▶HIV-protease inhibitors(atazanavir, saquinavir)moderately to
markedly increase the exposure tomaraviroc. Refer to
specialist literature.rStudy
▶HIV-protease inhibitors(darunavir)(boosted with ritonavir)
markedly increase the exposure tomaraviroc. Refer to
specialist literature.rStudy
▶HIV-protease inhibitors(lopinavir)(boosted with ritonavir)
moderately increase the exposure tomaraviroc. Refer to
specialist literature.rStudy
▶HIV-protease inhibitors(ritonavir)markedly increase the
exposure tomaraviroc. Refer to specialist literature.r
Study
▶Maravirocpotentially decreases the exposure toHIV-protease
inhibitors(fosamprenavir)andHIV-protease inhibitors
(fosamprenavir)potentially decrease the exposure to
maraviroc. Avoid.rStudy
▶Idelalisibmarkedly increases the exposure tomaraviroc.
Adjust dose.rTheoretical
▶Macrolides(clarithromycin)are predicted to markedly increase
the exposure tomaraviroc. Adjust dose.rStudy
▶Mitotaneis predicted to decrease the exposure tomaraviroc.
Adjust dose.rStudy
▶Rifampicinis predicted to decrease the exposure tomaraviroc.
Adjust dose.rStudy
▶St John’sWortis predicted to decrease the exposure to
maraviroc. Avoid.rTheoretical
Measles, mumps and rubella vaccine, live→see live vaccines
Mebendazole
▶H 2 receptor antagonists(cimetidine)increase the concentration
ofmebendazole.oStudy
Medroxyprogesterone
▶Sugammadexis predicted to decrease the exposure to
medroxyprogesterone. Use additional contraceptive
precautions.rTheoretical
Mefenamic acid→see NSAIDs
Mefloquine→see antimalarials
Melatonin→seeTABLE 11p. 849 (CNS depressant effects)
▶Antiepileptics(phenytoin)are predicted to decrease the
exposure tomelatonin.oTheoretical
▶Combined hormonal contraceptivesare predicted to increase
the exposure tomelatonin.oTheoretical
▶HIV-protease inhibitors(ritonavir)are predicted to decrease the
exposure tomelatonin.oTheoretical
▶Leflunomideis predicted to decrease the exposure to
melatonin.oTheoretical
▶Quinolones(ciprofloxacin)are predicted to increase the
exposure tomelatonin.oTheoretical
▶Rifampicinis predicted to decrease the exposure tomelatonin.
oTheoretical
▶SSRIs(fluvoxamine)very markedly increase the exposure to
melatonin. Avoid.rStudy
▶Teriflunomideis predicted to decrease the exposure to
melatonin.oTheoretical
Meloxicam→see NSAIDs
Melphalan→see alkylating agents
Memantine
▶Dopamine receptor agonists(amantadine)increase the risk of
CNS toxicity when given withmemantine. Use with caution or
avoid.rTheoretical
▶Memantineis predicted to increase the effects ofdopamine
receptor agonists(apomorphine, bromocriptine, cabergoline,
pergolide, pramipexole, quinagolide, ropinirole, rotigotine).
oTheoretical
▶Memantineis predicted to increase the risk of CNS side-effects
when given withketamine. Avoid.rTheoretical
▶Memantineis predicted to increase the effects oflevodopa.
oTheoretical
Mepacrine
▶Mepacrineis predicted to increase the concentration of
antimalarials(primaquine). Avoid.oTheoretical
Mepivacaine→see anaesthetics, local
Meprobamate→seeTABLE 11p. 849 (CNS depressant effects)
Meptazinol→see opioids
Mercaptopurine→seeTABLE 1p. 847 (hepatotoxicity),TABLE 15p. 850
(myelosuppression)
▶Allopurinolpotentially increases the risk of haematological
toxicity when given withmercaptopurine. Adjust
mercaptopurinedose,p. 543.rStudy
▶Mercaptopurinedecreases the anticoagulant effect of
coumarins.oAnecdotal
▶Febuxostatis predicted to increase the exposure to
mercaptopurine. Avoid.rTheoretical
▶Live vaccinesare predicted to increase the risk of generalised
infection (possibly life-threatening) when given with
mercaptopurine(high-dose). Public Health England advises
avoid (refer to Green Book).rTheoretical
Meropenem→see carbapenemsBNFC 2018 – 2019 Macrolides—Meropenem 951
Interactions|Appendix 1A1