Co-administered drugs that can inhibit CYP3A4 (e.g. ritonavir, itraconazole) have been shown to inhibit the metabolism of corticosteroids and the potency of the CYP3A4 inhibitor. The extent to which this interaction is clinically relevant depends on the dose and route of administatrion of the corticosteroids and the potency of the CYP3A4 inhibitor.
Following significant systemic absorption, neomycin sulphate can intensify and prolong the respiratory depressant effects of neuromuscular blocking agents.
Possibility of cumulative toxicity should be considered when neomycin is applied topically in combination with systemic aminoglycoside therapy.