Overview

Post-exposure prophylaxis (PEP) using doxycycline 200 mg within 24 hours of unprotected sexual intercourse to prevent sexually transmitted infections has demonstrated a reduction in the incidence of chlamydial and syphilis infections and syphilis infection by 70% and 73% in men who have sex with men (MSM) undergoing pre-exposure prophylaxis prophylaxis (PrEP) for HIV. Other studies are underway or in development on doxycycline prophylaxis for bacterial STIs, which are particularly common in this population. Monitoring adherence to PEP is of great interest in guaranteeing the effectiveness of this strategy and to be able to assess the uptake of PEP among PrEP users. Among the many methods for assessing adherence, measuring drug concentrations is a more accurate measure of adherence than self-reporting.

The therapeutic monitoring of doxycycline and the assessment of adherence have been described using plasma and hair samples, allowing estimation of intake over the last 3-4 days and 4 months, respectively. Nevertheless, these biological matrices present several limitations for application in clinical practice: reflecting the duration of exposure should be more in line with the frequency of visits (2 months), and the collection of hair samples may be difficult due to refusal or short hair. On the other hand, interpretation of the hair assay is limited by the degradation of doxycycline in this matrix, which could lead to underestimation of drug intake. By Therefore, new biological matrices are needed for more accurate assessment of doxycycline adherence in post-exposure prevention monitoring.

The objective is to evaluate the pharmacokinetics of doxycycline in plasma, whole blood, dried blood spots (DBS), urine and hair after a single dose of doxycycline in men using oral doxycycline for post-exposure prophylaxis of sexually transmitted infections (syphilis or Chlamydia trachomatis) and having sex with men.

Eligibility

Inclusion Criteria:

• Ages 18-44 years
• Assigned female at birth
• Crohn's Disease (CD) diagnosis
• In stable clinical remission from CD, defined as a short Crohn's Disease Activity Index (CDAI; See Table 3) \<150 without use of corticosteroids
• Self-reported primary dysmenorrhea
• Regular menstrual cycles occurring every 23-35 days
• Using an appropriate contraceptive method or abstinence

Exclusion Criteria:

• Any of the following conditions: endometriosis, adenomyosis, polycystic ovarian syndrome, endometrial fibroids/polyps, chronic pelvic inflammatory disease, a history of pelvic surgery including hysterectomy, any other pathological pelvic conditions, or current pregnancy
• Plans to become pregnant during the study period
• Use of an oral contraceptive for less than 3 months, on an unstable oral contraceptive dose within the last 3 months, switched from one oral contraceptive to another within the last 3 months or intend to do so during the course of the trial
• Taking hormone therapy including estrogen or progesterone that is not part of a hormonal contraceptive
• Known hypersensitivity or contraindication to ibuprofen or acetaminophen
• Inability to complete REDCap questionnaires (including confusion despite training and/or lack of smart phone and/or computer access).
• Not able to speak and read English language.