Background The role of oral drugs in gonorrhoea treatment is controversial, and the effect of eliminating oral treatments is unknown.

Methods We created an arithmetic model to estimate the number of treatment failures (including no treatment) among persons with gonorrhoea and their first generation sex partners comparing current treatment patterns to treatment using only intramuscular drugs. Our base case scenario assumed: decreased susceptibility in 2% and 5% of cases in heterosexuals and men who have sex with men (MSM), respectively; oral therapy use in 30% of heterosexuals and 15% of MSM; treatment failure in 10% of persons with decreased susceptibility gonorrhoea given oral therapy; elimination of oral therapy results in 5% of oral treatment patients going untreated; expedited partner therapy (EPT) is offered to 40% of heterosexuals and increases the number of infected partners treated per case by 0.165.

Results In our base case scenario, elimination of oral treatment decreased the number of decreased susceptibility treatment failures relative to the total number of decreased susceptibility cases by 0.8% if one ignores the effect of EPT, and increased decreased susceptibility cases by 0.8% with an EPT effect included. Total gonorrhoea cases increased by 0.8% and 4%, with and without an EPT effect, respectively. Assuming 50% of heterosexuals and 25% of MSM receive oral therapy at baseline and that 20% of decreased susceptibility cases fail oral treatment, elimination of oral therapy diminished decreased susceptibility cases 2.6% and 1.4% with and without an EPT effect, respectively, while increasing total gonorrhoea cases 1.5–4.8%.

Conclusions Given plausible current levels of treatment efficacy, eliminating oral gonorrhoea therapy in the U.S. would likely have a small effect on decreased susceptibility treatment failures, and would somewhat increase gonorrhoea morbidity. These findings do no incorporate longer-term transmission effects, but highlight the importance of developing effective oral gonorrhoea treatment options.