ArticleBMC musculoskeletal disorders2021
Effect of low-dose amitriptyline on reducing pain in clinical knee osteoarthritis compared to benztropine: study protocol of a randomised, double blind, placebo-controlled trial.
Article in BMC musculoskeletal disorders, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 4 papers.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
4 citing papers in PubMed, 17 citations in OpenAlex.
- Pain Phenotype in Knee Osteoarthritis: Implications for Mechanism-Based Therapy.Orthopaedic surgery · 2025Review
- Prioritized polycystic kidney disease drug targets and repurposing candidates from pre-cystic and cystic mouse Pkd2 model gene expression reversion.Molecular medicine (Cambridge, Mass.) · 2023Article
- Antidepressants for pain management in adults with chronic pain: a network meta-analysis.The Cochrane database of systematic reviews · 2023Review
- Consensus Guidelines on Interventional Therapies for Knee Pain (STEP Guidelines) from the American Society of Pain and Neuroscience.Journal of pain research · 2022Review
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
8 authors at 3 institutions in 1 country.
Funding
Abstract
backgroundKnee osteoarthritis is a major cause of pain and disability. Pain control is poor, with most patients remaining in moderate to severe pain. This may be because central causes of pain, a common contributor to knee pain, are not affected by current treatment strategies. Antidepressants, such as amitriptyline, have been used to treat chronic pain in other conditions. The aim of this randomised, double blind, controlled trial, is to determine whether low dose amitriptyline reduces pain in people with painful knee osteoarthritis over 3 months compared to benztropine, an active placebo. METHODS/
designOne hundred and sixty people with painful radiographic knee osteoarthritis will be recruited via clinicians, local and social media advertising. Participants will be randomly allocated in a 1:1 ratio to receive either low dose amitriptyline (25 mg) or active placebo (benztropine mesylate, 1 mg) for 3 months. The primary outcome is change from baseline in knee pain (WOMAC pain subscale) at 12 weeks. Secondary outcomes include change in function (total WOMAC) and the proportion of individuals achieving a substantial response (≥ 50% reduction in pain intensity, measured by Visual Analog Scale, VAS, from no pain to worst pain imaginable, 0-100 mm) and moderate response (≥ 30% reduction in pain intensity, measured by VAS) at 12 weeks. Intention to treat analyses will be performed. Subgroup analyses will be done. DISCUSSION: This study will provide high level evidence regarding the effectiveness of low dose amitriptyline compared to benztropine in reducing pain and improving function in knee OA. This trial has the potential to provide an effective new therapeutic approach for pain management in knee osteoarthritis, with the potential of ready translation into clinical practice, as it is repurposing an old drug, which is familiar to clinicians and with a well described safety record.
trial registrationAustralian New Zealand Clinical Trials Registry prior to recruitment commencing ( ACTRN12615000301561 , March 31, 2015, amended 14 December 2018, February 2021). Additional amendment requested 18 July 2021.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the Socratic graph.