Tirzepatide and oral progestogens: A hypothesis-generating review of a biologically plausible pharmacokinetic interaction in gynaecologic disease control and menopausal hormone therapy

Tirzepatide, a dual incretin receptor agonist, is increasingly prescribed to women in midlife, many of whom also use oral progestogens for gynaecologic disease control or for endometrial protection during menopausal hormone therapy. Because tirzepatide delays gastric emptying, it may alter the absorption of co-administered oral drugs. This hypothesis-generating narrative review, based on a structured search of PubMed/MEDLINE, EMBASE and the Cochrane Library through February 2026, examines the biological plausibility of such an interaction and the limits of the current evidence. In the only available pharmacokinetic study, a single 5 mg dose of tirzepatide given with a combined oral contraceptive reduced the peak plasma concentration of ethinylestradiol, norgestimate and its active metabolite norelgestromin by 59%, 66% and 55%, and reduced overall exposure by 20%, 21% and 23% respectively, delaying time to peak by 2.5 to 4.5 h. The much smaller reduction in exposure to the active metabolite illustrates that a fall in peak concentration cannot be equated with reduced efficacy. No equivalent data exist for progestogens used in therapeutic gynaecologic or menopausal indications, and findings obtained with one contraceptive formulation cannot be extrapolated automatically to structurally different agents. The effect on gastric emptying is greatest after the first dose and diminishes with continued treatment, so any risk would be concentrated during initiation and dose escalation. Whether tirzepatide meaningfully alters the clinical effectiveness of oral progestogens is untested; the possibility is biologically plausible but unproven, and dedicated pharmacokinetic and prospective clinical studies are required.