2.5% Lidocaine/2.5% Prilocaine Cream for IUD Insertion and Endometrial Biopsy

The proposed study is a double-blind, placebo-controlled randomized controlled trial (RCT). Participants will be recruited from Mount Sinai Hospital outpatient gynecology clinics. Recruitment, consent, randomization, procedure and post-procedure survey will occur during the same visit.

Two separate randomization schedules will be generated, one for IUD insertion and one for endometrial biopsy, using computer-generated sequences prepared by an independent study coordinator. Randomization will occur via consecutively numbered, opaque, sealed envelopes containing the allocation code. Each participant will be randomly assigned to one of two arms: 1) Intervention (5g of 2.5% lidocaine/2.5% prilocaine cream in a pre-filled vaginal applicator). 2) Placebo (5g of VersaPro cream in a pre-filled vaginal applicator). The research coordinator (who is not involved in direct patient care) will open the allocation envelopes without the presence of the participant or the provider. They will prepare the self-applicators with either 5g of 2.5% lidocaine/2.5% prilocaine cream or 5g of placebo cream to maintain blinding. The patient will be instructed how to self-administer the applicator and dispense all 5g of cream into their vagina in the washroom. A patient education sheet highlighting instructions will also be provided. The patient will wait 10-15 mins and then will be brought into a room for the procedure. Once the procedure begins, pain scores at key intervals will be patient-reported by a 10-point numeric rating scale (NRS) and recorded by a research assistant. A global pain score using a 100mm visual analogue scale (VAS) at 5-minutes following the procedure will also be collected. Post-procedure, there will be a provider-completed questionnaire and a patient satisfaction questionnaire. The provider questionnaire will help describe details of the procedure and complications. The patient satisfaction questionnaire will describe feasibility, acceptability and satisfaction with self-administered cream. The primary outcome will be global pain score at 5-minutes post-procedure, which will be patient-reported by the 100 mm VAS. Secondary outcomes include: pain at specific pain points using a 10-point NRA (baseline after insertion of cream, after insertion of speculum, tenaculum placement, sounding of uterus (IUD only), IUD insertion or endometrial biopsy, and 1-minute post-procedure). Other secondary outcomes include pre- and post-procedure anxiety, procedural characteristics (uterine size, position, IUD type, number of biopsy passes), immediate complication and side effects, procedural difficulty, length of time to complete the procedure, and patient reported feasibility, acceptability, perceived control over pain and satisfaction.

Inclusion criteria

• Any participant ≥18 years presenting for an IUD insertion or endometrial biopsy
• English speaking participants only

Exclusion criteria

• Use of pain medication that is not an NSAID or acetaminophen (e.g. opioids, benzodiazepines) within past 24 hours
• Misoprostol administration within 24 hours
• Confirmed pregnancy
• Any diagnosed chronic pain syndromes (e.g. fibromyalgia, vaginismus)
• Allergy to lidocaine, prilocaine or any other "-caine" type anesthetics or any of the non-medicinal ingredients found in the product
• Patients with congenital or idiopathic methemoglobinemia
• Patients with glucose-6-phosphate dehydrogenase deficiency
• Severe kidney or liver disease
• Previous history of local anesthetic systemic toxicity (LAST)
• Baseline vital signs of systolic blood pressure <100, diastolic blood pressure <60 and/or pulse <60.
• Previous unsuccessful office attempt of IUD insertion or endometrial biopsy by the same practitioner (note of clarification: previous unsuccessful IUD insertion or biopsy attempt by a different practitioner will still be eligible)
• Active atopic dermatitis or skin involving vulva, vagina and/or cervix.