Penicillin G

22 interactions
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by Dr. Brian Staiger, PharmD, BCPS · Updated Jul 11, 2026 · Editorial policy · Data sources

Sources: FDA prescribing information (Structured Product Labeling), the published literature cited in each entry, DDInter 2.0 (a major open-access drug-interaction database), and legacy DrugBank interaction data distributed by the NIH's RxNav service (decommissioned in 2024) — analyzed and reviewed by our pharmacist team. How we build this library →

Most serious with: Demeclocycline Levonorgestrel Intrauterine System Minocycline Estradiol Estradiol Topical Hydroxychloroquine
14 Major 2 Moderate 6 Minor
All (22) Major (14) Moderate (2) Minor (6)

Major

Penicillin G Demeclocycline Declomycin® Decreased antibacterial effectiveness Details Penicillin G Doxycycline Injection Acticlate Decreased antibacterial effectiveness Details Penicillin G Eravacycline Injection Xerava Decreased antibacterial effectiveness Details Penicillin G Estradiol Delestrogen Decreased contraceptive effectiveness Details Penicillin G Estradiol Topical Divigel Decreased contraceptive effectiveness Details Penicillin G Estradiol Transdermal Patch Alora® Decreased contraceptive effectiveness Details Penicillin G Exenatide Injection Bydureon Reduced oral antibiotics absorption and reduced efficacy of oral antibiotics Details Penicillin G Hydroxychloroquine Plaquenil An increased risk of seizures Details Penicillin G Levonorgestrel After banger Decreased contraceptive effectiveness Details Penicillin G Levonorgestrel Intrauterine System Kyleena Decreased contraceptive effectiveness Details Penicillin G Methotrexate Jylamvo Increased methotrexate exposure, an increased risk of methotrexate-related severe adverse reactions, reduced active metabolite for... Details Penicillin G Methotrexate Injection Abitrexate® Increased methotrexate exposure, an increased risk of methotrexate-related severe adverse reactions, reduced active metabolite for... Details Penicillin G Minocycline Amzeeq Decreased antibacterial effectiveness Details Penicillin G Minocycline Topical Amzeeq Decreased antibacterial effectiveness Details

Moderate

Penicillin G Cholestyramine Resin Locholest® Decreased penicillin G absorption Details Penicillin G Lixisenatide Injection Adlyxin® Delayed therapeutic effect Details

Minor

Penicillin G Amikacin Injection Amikin® Loss of aminoglycoside efficacy Details Penicillin G Amikacin Oral Inhalation Arikayce Loss of aminoglycoside efficacy Details Penicillin G Chloramphenicol Injection Chloromycetin® Injection Decreased antibacterial effectiveness Details Penicillin G Gentamicin Injection Garamycin® I.V. Loss of aminoglycoside efficacy Details Penicillin G Gentamicin Ophthalmic Garamycin® Ophthalmic Loss of aminoglycoside efficacy Details Penicillin G Gentamicin Topical Garamycin® Loss of aminoglycoside efficacy Details

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Educational information only, not medical advice. Always confirm interactions with your pharmacist or prescriber before making any change to your medications.