Study team has decided to close the trial (NCT05405257) due problems with patient recruitment and enrollment efforts. To date, only one patient completed both arms.

The purpose of this pilot study is to evaluate effect of IV oxytocin on chronic pain in patients with Hypermobile Ehlers Danlos syndrome.

This will be a single-site study to evaluate the effect of IV oxytocin on chronic pain in female adult patients with hypermobile EDS.

Oxytocin secretion in the body is dynamic and can be affected by multiple factors including the menstrual period. In order to have minimum variation between tested individuals we conduct this study in females at the same stage of their menstrual cycles. Hypermobile EDS is more prevalent in females and the symptoms are usually more severe in females and more females come to medical attention. We are not aware of any difference in the risk from using oxytocin in females vs males.

All participating individuals are affected with hypermobile-EDS (hEDS) with chronic moderate to severe pain. Study will include two periods of treatment - one with placebo and one with oxytocin and a one month period will be held in between the two treatments. Participants will be blinded to the order of treatment. Each period of treatment will start 7-10 days after the beginning of the menstrual cycle and will include 6 days of daily subjective pain evaluation using pain-evaluation questionnaire ('preinfusion evaluation') followed by three consecutive daily infusions (placebo or oxytocin). Response to treatment will be evaluated by questionnaire during 6 days after each three infusion days (placebo or oxytocin) . Additional questionnaires for evaluation of anxiety and depression will be used as well. Patients will be asked to wear ACTIHEART device (measures heart rate, heart rate variation, and activity levels) 3 days prior to infusion, during the 3 days of infusion, and in the 3 days after the last infusion day. For each infusion period, participants will arrive to the study site for three daily consecutive visits, each will last for 3-4 hours. Response variables will be collected prior, during and after each infusion. Patients will fill out pain evaluation questionnaires pre and post infusion and some questionnaires during the days of infusion. Blood pressure and heart rate measurements will be taken prior, during and after the infusion. Blood samples for measurements of oxytocin levels and blood samples for future analysis will be collected in some of the infusion days (before and after the infusion).

Inclusion Criteria:

1) Premenopausal Females, Age >18 years 2) Clinical diagnosis of hypermobile EDS according to the 2017 criteria for hEDS 3) Menstrual periods (range from 8 to 42 days) 4) Pain level greater that pain score of 4 out of 10 on a Numeric Rating Scale in at least two of the following locations: back, neck, shoulders, elbows, wrist, hand joints, hips, knees, ankles, on most days over the 3 months preceding enrollment. 5) On a stable regimen for pain control without any expected increase in dose of pain medications during the study period. 6) All participants should have a negative urine pregnancy test and agree to use an acceptable method of contraception (abstinence or barrier methods).

Exclusion Criteria:

1) Known allergy to OXT or preservatives in the medication 2) Pregnancy 3) Lactation 4) A confirmed clinical diagnosis of autoimmune disorders that lead to joint inflammation and joint pain such as SLE, RA, psoriatic arthritis, ankylosing spondylitis, scleroderma, and enteropathic arthritis 5) History of known cardiac arrhythmias (except for asymptomatic sinus tachycardia and sinus bradycardia) 6) Heart rate persistently greater than 110/min or less than 50 per minute 7) QTC of > 450 ms from EKG (electrocardiogram) test 8) Taking oral or other hormonal contraceptives 9) Individuals with a clinical condition which, in the view of the investigator compromises safety 10) Participating in another interventional study.

2 months

none was reported

Participant will be blinded to the sequence of treatment (which was fixed). Infusion bags containing either the placebo and drug will not be labeled or known to the participant.