Moderate. These medicines may cause some risk when taken together. Contact your healthcare professional (e.g. doctor or pharmacist) for more information.
How the interaction occurs:
When these two medicines are taken together, tetracycline may interfere with the beneficial effects of penicillin.
What might happen:
A decrease in the beneficial effects of your penicillin antibiotic may occur, which would decrease the effectiveness in treating your infection.
What you should do about this interaction:
Contact your healthcare professionals (e.g. doctor or pharmacist) as soon as possible about taking these two medicines together. If it is essential that both these medicines be taken, take the penicillin and tetracycline on a schedule that separates them by as many hours as possible.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.
1.Lepper MH, Dowling HF. Treatment of pneumococcic meningitis with penicillin compared with penicillin plus aureomycin. Am Med Assoc Arch Intern Med 1951;88:489-94.
2.Olsson RA, Kirby JC, Romansky MJ. Pneumococcal meningitis in the adult. Clinical, therapeutic, and prognostic aspects in forty-three patients. Ann Intern Med 1961 Oct;55(4):545-9.