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Ibuprofen Gel or Capsaicin Cream for my Painful Knee Osteoarthritis?

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
ClinicalTrials.gov Identifier: NCT03146689
Recruitment Status : Completed
First Posted : May 10, 2017
Last Update Posted : April 18, 2019
Arthritis Research UK Pain Centre
Nottingham University Hospitals Charity
Information provided by (Responsible Party):
University of Nottingham

Brief Summary:

Despite evidence that topical non-steroidal anti-inflammatory drugs (NSAIDs) and capsaicin are effective in osteoarthritis (OA), it is still unclear why they work for some people but not others. The investigators are undertaking an individual patient data (IPD) meta-analysis to identify responders according to patient characteristics, however, no studies report the presence of synovial hypertrophy or neuropathic-like pain. These two traits are of interest as they may be used to optimise the treatment effects of the two drugs which work via different mechanisms to reduce pain in OA. The investigators are therefore conducting this pilot n-of-1 trial series.

This pilot n-of-1 trial series will investigate whether a person with OA, who has a different balance between inflammatory and neuropathic pain, shows a preference between these mechanistically different treatments. The trial will also be used to offer recommendations on the use of n-of-1 trial series for individualised (precision) medicine in OA.

Condition or disease Intervention/treatment Phase
Osteoarthritis, Knee Drug: Topical NSAID Drug: Topical Capsaicin Not Applicable

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 22 participants
Allocation: N/A
Intervention Model: Single Group Assignment
Intervention Model Description: N-of-1 trial series: several within-individual, randomised, multiple cross-over trials aggregated into a series.
Masking: None (Open Label)
Primary Purpose: Other
Official Title: Identifying Treatment Responders to a Topical Non-steroidal Anti-inflammatory Drug (NSAID) or Topical Capsaicin in Painful Knee Osteoarthritis: A Pilot Series of N-of-1 Trials
Actual Study Start Date : August 4, 2017
Actual Primary Completion Date : October 16, 2018
Actual Study Completion Date : October 16, 2018

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Osteoarthritis

Arm Intervention/treatment
Experimental: Topical NSAID and topical capsaicin

Within each participant:

Topical NSAID (A) or capsaicin (B) are taken for a treatment period of four weeks. This is followed by another four week treatment period with the other treatment. These two treatment periods comprise one treatment cycle. The order of treatments within a treatment cycle is determined randomly (AB or BA).

This treatment cycle is repeated so that all participants undergo a maximum of three topical NSAID treatment periods and three topical capsaicin treatment periods (i.e., three treatment cycles). This is reduced to two cycles if they are found to meet the criteria for response at the interim analysis (after cycle two).

Drug: Topical NSAID
Applied four times daily
Other Name: Ibuprofen 5% gel

Drug: Topical Capsaicin
Applied four times daily
Other Name: Zacin 0.025% cream

Primary Outcome Measures :
  1. Change from baseline knee pain on 0-10 numeric rating scale (NRS) [ Time Frame: Baseline and end of each treatment period (i.e., after four weeks of treatment) ]
    Pain experienced in the most painful knee in the past week will be recorded. The following question will be asked for this purpose: "In the past week, on average, how intense was your knee pain rated on a 0-10 scale, where 0 is 'no pain' and 10 is 'pain as bad as could be'?". The change in pain score between period baseline and period end will be calculated

Secondary Outcome Measures :
  1. End-of-cycle treatment preference [ Time Frame: At the end of each treatment cycle (i.e., after 4 weeks of NSAID and 4 weeks of capsaicin). ]
    "Considering only the pain relief experienced in this most recent cycle, which treatment do you feel provided satisfactory pain relief?"

  2. End-of-study overall treatment preference [ Time Frame: At study completion - following six treatment periods (24 weeks of treatment, excluding washouts) or 4 treatment periods for responders at the interim analysis (16 weeks of treatment, excluding washouts) ]
    "Considering all the aspects of the treatment, including its effectiveness and ease of application, which treatment do you prefer?"

  3. Weekly knee pain on 0-10 numeric rating scale (NRS) [ Time Frame: At end of week 1, week 2, week 3, and week 4 of each treatment period. ]
    Pain experienced in the most painful knee in the past week will be recorded. The following question will be asked for this purpose: "In the past week, on average, how intense was your knee pain rated on a 0-10 scale, where 0 is 'no pain' and 10 is 'pain as bad as could be'?".

Information from the National Library of Medicine

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Ages Eligible for Study:   40 Years to 95 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Men and non-pregnant women who have had ultrasound and radiographic assessments in the Knee Pain in the Community study

    o Premenopausal women will need to be on an acceptable contraceptive method

  • Aged 40-95 years
  • Knee pain between 4-8 on the NRS
  • Knee osteoarthritis - defined as knee pain plus radiographic changes, based on previous questionnaire responses and radiographic findings

    • Knee pain: individuals with knee pain in and around the knee on most days for at least a month.
    • Radiographic changes: definite joint space narrowing and definite osteophytes (each scoring two or more on the Nottingham Line Drawing Atlas) in the tibiofemoral and/or patellofemoral compartments
  • Predominantly neuropathic or inflammatory phenotypes based on previous questionnaire responses (not current status)

    • Predominantly neuropathic phenotype: painDETECT Questionnaire (PDQ) > 13 and synovial hypertrophy (SH) <4 mm
    • Predominantly inflammatory phenotype: SH > 4 mm and PDQ < 13
    • If we cannot recruit enough people with the above thresholds, we will base recruitment on the overall distribution of PDQ and SH scores from the population. The third tertile of PDQ and the first tertile of SH for neuropathic and the first tertile of PDQ and the third tertile of SH for inflammatory phenotypes.

Exclusion Criteria:

  • Inability to give informed consent
  • Daily use of oral NSAIDs for the last two weeks
  • Prior use of Ibuprofen gel or Zacin on the affected knee(s)
  • Terminal or untreated major mental illness
  • Pregnancy or breastfeeding
  • Hypersensitivity or allergy to topical NSAIDs, capsaicin, or other ingredients in the preparations. This includes individuals that experience attacks of asthma, urticaria, or acute rhinitis that are precipitated by NSAIDs
  • Current treatment for stomach or duodenal ulcers
  • Total joint replacement of affected joint
  • Renal failure
  • Taking anticoagulants

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03146689

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United Kingdom
Academic Rheumatology, University of Nottingham
Nottingham, Nottinghamshire, United Kingdom, NG5 1PB
Sponsors and Collaborators
University of Nottingham
Arthritis Research UK Pain Centre
Nottingham University Hospitals Charity
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Principal Investigator: Weiya Zhang, PhD University of Nottingham
Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
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Responsible Party: University of Nottingham
ClinicalTrials.gov Identifier: NCT03146689    
Other Study ID Numbers: B 10022017
First Posted: May 10, 2017    Key Record Dates
Last Update Posted: April 18, 2019
Last Verified: April 2019
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Yes
Plan Description: Requests for the IPD can be made to the Prof Weiya Zhang. Raw de-identified data may be shared
Supporting Materials: Study Protocol
Time Frame: After publication of the study

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Keywords provided by University of Nottingham:
Additional relevant MeSH terms:
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Osteoarthritis, Knee
Joint Diseases
Musculoskeletal Diseases
Rheumatic Diseases
Anti-Inflammatory Agents, Non-Steroidal
Analgesics, Non-Narcotic
Sensory System Agents
Peripheral Nervous System Agents
Physiological Effects of Drugs
Anti-Inflammatory Agents
Antirheumatic Agents
Cyclooxygenase Inhibitors
Enzyme Inhibitors
Molecular Mechanisms of Pharmacological Action
Dermatologic Agents