A Phase 3 interventional study of Etoricoxib + Tizanidine fixed dose and Etoricoxib fixed dose in Acute Low-back Pain and Muscle Spasm; Back Pain, sponsored by Laboratorios Silanes S.A. de C.V.. Completed at 1 site in Mexico. Open to participants aged 18 Years to 70 Years. Per ClinicalTrials.gov, last updated 2026-01-09.
Sponsored by Laboratorios Silanes S.A. de C.V. · Phase 3, Interventional, and Treatment
This is a Phase III, longitudinal, multicenter, randomized, double-blind clinical trial. The aim of the study is to evaluate the efficacy and safety of a fixed-dose combination of etoricoxib and tizanidine compared to etoricoxib alone in patients with acute low back pain associated with muscle spasms.
Researchers will compare the efficacy of a fixed-dose combination of etoricoxib and tizanidine versus etoricoxib alone in the treatment of acute low back pain associated with muscle spasms. Efficacy will be assessed by evaluating the average change in pain among patients who report improvement over the 7-day follow-up period. Adverse events related to the interventions will be recorded throughout the study.
Participants will:
123 studies on the registry are indexed under Spasm; 7 are open to participants now.
This study's enrollment of 136 is above the median of 80 across 104 interventional studies indexed under Spasm.
Browse Spasm studies →Laboratorios Silanes S.A. de C.V. is the lead sponsor of 45 studies on the registry; 1 is open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
The New York Heart Association’s four classes of how much heart failure limits physical activity.
Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.
A score of how well the liver works in people with liver disease such as cirrhosis: class A is mild, B moderate and C severe.
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
NYHA class (heart failure)
The New York Heart Association’s four classes of how much heart failure limits physical activity.
Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Child-Pugh class
A score of how well the liver works in people with liver disease such as cirrhosis: class A is mild, B moderate and C severe.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
GFR and eGFR (kidney filtering)
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Metastases
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Life expectancy
The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Administered orally, 1 sachet a day for 7 days.
Drug: Etoricoxib + Tizanidine fixed dose
Administered orally, 1 sachet a day for 7 days.
Drug: Etoricoxib fixed dose
One sachet with 120 mg / 4 mg, dissolved in 100 mL of water
Also known as: Etori + Tiza
One sachet with 120 mg, dissolved in 100 mL of water
Also known as: Etori
Comparison of the percentage change in pain intensity, as measured by the Visual Analog Scale (VAS), on Days 1, 3, 5, and 7 of follow-up relative to baseline, within each treatment group.
The Visual Analog Scale (VAS) for pain is a straight line anchored by two descriptors: one end indicating no pain and the other representing the worst pain imaginable. The investigator will administer the VAS at each study visit to assess pain intensity. At the end of the clinical trial, the percentage change in pain scores from baseline will be calculated and compared between treatment groups.
Time frame: 7 days
Number of participants reporting treatment-related adverse events, as documented in the patient diary.
To describe the frequency, intensity, and causality of adverse events reported during the clinical trial, stratified by treatment group. Adverse events will be recorded by patients in their diary logs. Each event will be monitored and followed up at the discretion of the investigator.
Time frame: 7 days
Analyze the percentage change in pain intensity, as measured by the Visual Analog Scale (VAS), on Days 1, 3, 5, and 7, compared to baseline, within and between each treatment group.
The Visual Analog Scale (VAS) for pain is a straight line anchored by two descriptors: one end represents the absence of pain, and the other indicates the worst pain imaginable. The investigator will administer the VAS at each study visit to assess pain intensity. At the end of the clinical trial, the percentage change in pain scores from baseline will be calculated and compared across treatment groups. Patients will attend in-person visits on Days 0, 3, and 7 of follow-up, and the investigator will conduct follow-up phone calls on Days 1 and 5.
Time frame: 7 days
Compare the proportion of patients in each treatment group who achieve a ≥30% reduction in pain intensity, as measured by the Visual Analog Scale (VAS), on Days 1, 3, 5, and 7 relative to baseline.
The Visual Analog Scale (VAS) for pain is a unidimensional tool consisting of a straight line anchored by two descriptors: one end indicating "no pain" and the other representing "the worst pain imaginable." The investigator will administer the VAS at each study visit to assess pain intensity. The proportion of patients achieving a reduction in pain of more than 30% from baseline will be recorded and compared across treatment groups on Days 1, 3, 5, and 7.
Time frame: 7 days
Compare the proportion of patients in each treatment group who achieve a ≥50% reduction in pain intensity, as measured by the Visual Analog Scale (VAS), on Days 1, 3, 5, and 7 relative to baseline.
The Visual Analog Scale (VAS) for pain is a straight line anchored by two descriptors: one end represents the absence of pain, and the other indicates the worst pain imaginable. The investigator will administer the VAS at each study visit to evaluate pain intensity. The proportion of patients achieving a pain reduction greater than 30% from baseline will be documented and compared across treatment groups on Days 1, 3, 5, and 7.
Time frame: 7 days
Determine the follow-up time point at which each treatment group demonstrates the greatest reduction in pain intensity, as measured by the Visual Analog Scale (VAS).
The Visual Analog Scale (VAS) for pain is a unidimensional measurement tool represented by a straight line anchored by two descriptors: one end indicating "no pain" and the other representing "the worst pain imaginable." The investigator will administer the VAS at each study visit to assess the patient's pain intensity.
Time frame: 7 days
Compare the proportion of patients in each treatment group according to the severity of lumbar muscle spasm, as assessed by the Investigator's Global Subjective Assessment.
The investigator will assess the severity of lumbar muscle spasm using a global subjective scale, which will also allow evaluation of the muscle's response to movement following administration of the study treatment.
Time frame: 7 days
Assess and compare the degree of physical disability caused by acute low back pain, as measured by the Oswestry Disability Questionnaire, on Days 3 and 7 in each treatment group, relative to baseline.
The Oswestry Disability Questionnaire is designed to assess how back pain affects a patient's ability to perform daily activities. It categorizes quality of life into five levels: no disability, mild disability, moderate disability, severe disability, and complete disability. The degree of disability will be assessed and compared between treatment groups.
Time frame: 7 days
Assess and compare the degree of disability in performing daily activities due to low back pain, as reported using the Roland-Morris Disability Questionnaire, on Days 3 and 7 in each treatment group, relative to baseline.
The Roland-Morris Disability Questionnaire is designed to assess functional mobility and limitations in daily activities due to low back pain. It consists of 24 items, with higher scores indicating a greater degree of disability. A maximum score of 24 reflects the most severe disability. The degree of disability will be assessed and compared between treatment groups.
Time frame: 7 days
Report the percentage of therapeutic adherence on Day 7 of the intervention, in each treatment group.
Therapeutic adherence will be defined by the principal investigator. Adherence will be considered adequate when the patient has taken ≥80% of the prescribed doses by the time of the corresponding evaluation.
Time frame: 7 days
Report the number of patients in each treatment group who require the use of rescue medication during the clinical trial.
The designated rescue medication will be acetaminophen 500 mg. If a patient feels the need for rescue medication, they must contact the study physician. The physician will assess the patient's pain using the Visual Analog Scale (VAS) via telephone. If deemed appropriate, the physician will authorize the use of the rescue medication.
Time frame: 7 days
Report the number of patients who experience therapeutic failure during the study, stratified by treatment group.
Therapeutic failure will be defined by the principal investigator following a medical consultation. The following criteria must be met: a decrease of less than 10 mm or an increase in pain intensity on the Visual Analog Scale (VAS) compared to baseline, along with a treatment adherence rate of ≥80%.
Time frame: 7 days
Plan to share: No
This study is completed, as verified in Jan 2026. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Laboratorios Silanes S.A. de C.V. →