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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
Benztropine for the relief of acute non-traumatic neck pain – a randomised trial
Scientific title
In patients presenting to the emergency department with acute non-traumatic neck pain, does benztropine compared to placebo relieve pain
Secondary ID [1] 280185 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Acute non-traumatic neck pain 286169 0
Condition category
Condition code
Musculoskeletal 286363 286363 0 0
Other muscular and skeletal disorders
Anaesthesiology 286380 286380 0 0
Pain management

Study type
Description of intervention(s) / exposure
a single dose of 2mg by intra-muscular injection (IM) of benztropine (volume of 2ml) will be administered.
Intervention code [1] 284553 0
Treatment: Drugs
Comparator / control treatment
2ml of IM normal saline
Control group

Primary outcome [1] 286820 0
The mean change in pain scores will be compared between the two groups, as measured by the treating doctor using the verbal numeric rating scale. With the verbal numeric rating scale the patient will be asked to score their pain from 0 to 10 with 0 indicating no pain, and 10 indicating the worst pain imaginable.
Timepoint [1] 286820 0
Time 0 and at time 30 minutes after the injection
Secondary outcome [1] 296732 0
Range of neck motion in 4 directions in degrees: flexion, extension, rotation to left, rotation to right. Measurement will be done with a universal goniometer.
Timepoint [1] 296732 0
Time 0 and at time 30 minutes after the injection

Key inclusion criteria
-Non-traumatic neck pain of <24 hours duration
-Age 16-65
Minimum age
16 Years
Maximum age
65 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
-Use of drugs known to cause dystonic reactions in the 24 hours prior to the onset of pain (eg metoclopramide (maxalon), prochlorperazine (stemetil), promethazine (phenergan), haloperidol)
-Clinical suspicion of a secondary cause for pain (eg neck-space infections, cervical osteomyelitis, discitis, epidural abscess, pathological cervical fractures, primary or secondary malignancies)
-Past history of cervical spine fracture
-Past history of chronic or recurrent neck pain
-Past history of cervical spine surgery
-Focal neurological deficit
-Known allergy or adverse event to benztropine
-Anti-coagulant medication (eg warfarin or enoxaparin) or clopidogrel
-Known coagulation disorder (eg haemophilia) or platelet disorder (eg ITP, leukaemia, myelodysplastic disorder)
-Parkinsons disease
-Pregnant women

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
The treating doctor will order the medication to be given by writing on a medication chart “benztropine or placebo 2ml IM. The medication chart will be given to the emergency department 'team co-ordinator'. Randomisation will then occur by opening sequentially numbered envelopes which are sealed and opaque in which the study allocation has been randomly assigned. These envelopes will be stored with the 'team co-ordinator'. Also, sealed inside will be a data collection sheet. The envelope will be opened by the ‘team co-ordinator’ who will then draw up the appropriate study drug. The team co-ordinator will then give the study drug to the nurse looking after the participant, and the data collection sheet to the doctor looking after the participant. The team co-ordinator will not divulge the contents of the syringe. Instructions in the envelope will re-enforce to the team co-ordinator not to divulge the contents of the syringe. While it would be ideal to have benztropine and saline in matching vials labelled A or B, funding constraints make this option unavailable. The team co-ordinator has been chosen as the person to draw up the study drug as they work in an area of ED physically distant from the clinic/consulting area where participants will be enrolled and treated. This means that the doctor, nurse and patient will be physically distant from the 'team co-ordinator' minimising the chance of accidental un-blinding. This method has been successfully used previously in this emergency department for a clinical trial.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
The randomisation sequence was computer generate utilising block randomisation methods to ensure balanced numbers in each group.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s

The people assessing the outcomes
Intervention assignment
Other design features
Phase 4
Type of endpoint(s)
Statistical methods / analysis

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment postcode(s) [1] 5155 0

Funding & Sponsors
Funding source category [1] 284976 0
Self funded/Unfunded
Name [1] 284976 0
Address [1] 284976 0
Country [1] 284976 0
Primary sponsor type
St George Hospital
Gray St
NSW, 2217
Secondary sponsor category [1] 283842 0
Name [1] 283842 0
Address [1] 283842 0
Country [1] 283842 0

Ethics approval
Ethics application status
Ethics committee name [1] 286981 0
Northern Sydney Central Coast Area Health Service Human Research Ethics Committee (Harbour)
Ethics committee address [1] 286981 0
Royal North Shore Hospital
Reserve Road, St Leonards, NSW 2065
Ethics committee country [1] 286981 0
Date submitted for ethics approval [1] 286981 0
Approval date [1] 286981 0
Ethics approval number [1] 286981 0

Brief summary
Patients present to the Emergency department with acute cervical muscle spasm and pain, which may be spontaneous in onset or related to non-traumatic twisting events. In lay speech this may be referred to as a ‘wry neck’. Conventional analgesics such as paracetamol, NSAIDs and oral opoids are the mainstay of treatment for wry neck, but often provide inadequate pain relief. Centrally acting anti-cholinergic drugs are used for the relief of pain/spasm from the chronic condition of idiopathic cervical dystonia and from drug induced dystonic reactions. The use of these drugs for acute spasmodic neck pain has been poorly studied. There is a single study in the literature assessing the centrally-acting anti-cholinergic drug benztropine (trade name cogentin) in the relief of pain and spasm from this condition. This is a case series of 5 patients with acute pain and spasm of the neck and demonstrated remarkable relief of pain and improvement in range of motion in all patients following an intra-muscular injection of benztropine.
Our hypothesis is that IM benztropine will provide relief of neck pain and improve range of neck movement in patients presenting with wry neck. We aim to compare the effect of 2mg IM benztropine with placebo on pain scores and range of motion in patients presenting to the ED with wry neck.
Trial website
Trial related presentations / publications
Asha SE, Kerr A, Jones K, McAlpine A. Benztropine for the relief of acute non-traumatic neck pain (wry neck) – a randomised trial. Emergency medicine journal. Published Online First, 20 November 2014: doi:10.1136/emermed-2014-204317
Public notes

Principal investigator
Name 33953 0
Dr Stephen Asha
Address 33953 0
Emergency Department, St George Hospital Gray St, Kogarah, NSW, 2217
Country 33953 0
Phone 33953 0
+61 2 9113 1650
Fax 33953 0
+61 2 9113 3946
Email 33953 0
Contact person for public queries
Name 17200 0
Dr Dr Stephen Asha
Address 17200 0
Emergency Department, St George Hospital
Gray St, Kogarah, NSW, 2217
Country 17200 0
Phone 17200 0
+61 2 9113 1650
Fax 17200 0
+61 2 9113 3946
Email 17200 0
Contact person for scientific queries
Name 8128 0
Dr Dr Stephen Asha
Address 8128 0
Emergency Department, St George Hospital
Gray St, Kogarah, NSW, 2217
Country 8128 0
Phone 8128 0
+61 2 9113 1650
Fax 8128 0
+61 2 9113 3946
Email 8128 0

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary