Double-blind, Randomized Controlled Study to Assess the Analgesic Effect of 2 g of Magnesium Dipyrone (Metamizol) and Changes in Plasma Beta-endorphin Immunoreactivity Values in Patients Undergoing Elective Inguinal Herniorrhaphy Under Epidural Anesthesia.

Antonio Martín Duce60 enrolled

Overview

A double-blind, randomized controlled study is designed to assess the analgesic effect of a single intravenous dose of 2 g of magnesium dipyrone (metamizol) and whether the administration of the active drug will be associated with changes in plasma beta-endorphin immunoreactivity values in patients undergoing elective inguinal herniorrhaphy (Bassini operation) under epidural anesthesia. Participants, care givers, and those assessing the outcomes will be blinded to group assignment. Participants will be randomized to receive dipyrone or a placebo. The active drug or placebo will be administered as an intravenous infusion over 10 min. Pain will be evaluated by the patient according to a 100-mm visual analogue scale. Assessments will be carried out the day before surgery, immediately after operation, at the time of drug administration, and 60 and 180 min after treatment. At the same time as pain will be evaluated, blood samples will be drawn for plasma beta-endorphin immunoreactivity measurement (immunoradiometric assay).

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

SUPPORTIVE_CARE

Masking

SINGLE

Enrollment

Conditions

Pain Beta-endorphin Dipyrone

Interventions

Dipyrone administrationDRUG

Dipyrone 2 g (Nolotil®, Europharma, Madrid, Spain); one ampoule in 50 mL of 0.9% saline solution as an intravenous infusion over 10 min.

Pain assessmentBEHAVIORAL

Pain will be evaluated by the patient according to a 100-mm visual analogue scale (VAS) (from point 0 "no pain" to point 10 "unbearable pain").

beta-endorphin immunoreactivityBIOLOGICAL

Plasma beta-EPIr levels will be measured by an immunoradiometric assay (Allegro Beta-endorphin, Nichols Institute Diagnostics, SAN JUAN DE CAPISTRANO, CA) (normal values 29-40 pg/mL). It will be obtained by venous blood samples (5 mL) at the same time points at pain will be measured.

Placebo administrationOTHER

Placebo in 50 mL of 0.9% saline solution as an intravenous infusion over 10 min.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 70 Years

Medical Language ↔ Plain English

Inclusion Criteria: * 18-70 years, elective surgery, routine laboratory tests (blood cell count, biochemical profile, urinalysis), chest radiography, twelve-lead electrocardiography, body mass index (BMI), blood pressure, pulse rate normal or abnormal values without clinical relevance and a mental status sufficient to be able to complete efficacy tests. Exclusion Criteria: * Patients who had taken other analgesics or anti-inflammatory drugs 24 h before surgery, as those with known hypersensitivity to the drug or with any other disorder contradicting the administration of dipyrone. Patients with hypersensitivity to non-steroidal anti-inflammatory agents.

Outcomes

Primary Outcomes

Analgesic efficacy-Pain relief

Visual Analogue Scale score

Time frame: 30 seconds

Secondary Outcomes

Beta-endorphins levels.

Beta-endorphin immunoreactivity levels

Time frame: 1 minute