The bioavailability of ethinyloestradiol and levonorgestrel in patients with an ileostomy

Preventive health measures in inflammatory bowel disease

“…Factors that may impair absorption of OC sex steroids, such as inflammation and ulceration of the intestinal mucosa, or more rapid transit of gastrointestinal contents in patients who have undergone bowel surgery, might reduce the efficacy of OCPs[118]. Two pharmacokinetic studies compared the absorption of combined OCPs between women with UC and healthy volunteers[119,120]. These studies found no significant differences in the absorption of OCPs among women with mild UC and those with an ileostomy following proctocolectomy with small ileal resections when compared with healthy women[119,120].…”

“…Two pharmacokinetic studies compared the absorption of combined OCPs between women with UC and healthy volunteers[119,120]. These studies found no significant differences in the absorption of OCPs among women with mild UC and those with an ileostomy following proctocolectomy with small ileal resections when compared with healthy women[119,120]. It was also noted that women with the largest bowel resections and continent ileostomies had the absolute lowest plasma levels of 1-norgestrel, however the plasma levels never dropped below the threshold needed to inhibit ovulation[120].…”

FFPRHC Guidance (April 2005) Drug interactions with hormonal contraception

“…[21][22][23][24]26 EE and progestogens have a narrow therapeutic range, and a decrease in bioavailability may lead to decreased contraceptive efficacy. Table 1 lists those drugs that induce liver enzymes and relevant associated drugs that do not.…”

“…The efficacy of combined oral contraception (COC) does not appear to be reduced in this situation. 24 There is no enterohepatic circulation of progestogens and therefore antibiotics that eliminate colonic bacteria do not affect progestogen-only contraceptives (POCs). 4 After counselling, women using short courses of drugs that interact with hormonal contraception may choose to continue their current hormonal method even if additional contraception, such as condoms, is required.…”

Interactions with hormonal contraception

“…Ileostomy patients (who have no EHC) do not have significant changes to this half-life, giving further indirect evidence of the very small part the EHC makes to COC efficiency. 19 The International Consensus Statement 20 specifies that women taking tetracyclines and penicillins require other contraception in addition to COC, even though no study has consistently shown an effect on circulating EE levels. A literature review 21 highlights the lack of good evidence for antibiotics, except rifampicin, being responsible for COC failure, and lack of consistency in advice given to patients for using extra contraceptive precautions in data sheets.…”