The Effects of Apomorphine on Experimental and Clinical Pain in Patients With Chronic Radicular Pain

The Effects of the Dopamine Agonist (Apomorphine) on Experimental and Clinical Pain in Patients With Chronic Radicular Pain: a Randomized, Double-blind, Placebo-controlled, Cross-over Study

Status

Completed

Phases

Phase 4

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT02969629

Enrollment

Registered

2016-11-21

Start date

2012-12-31

Completion date

2014-12-31

Last updated

2016-11-22

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Chronic Low Back Pain

Brief summary

The study aimed to explore the effect of the dopamine agonist apomorphine on spontaneous pain intensity and evoked cold clinical and experimental pain in patients with lumbar radicular neuropathic pain (NP). Patients received either apomorphine or placebo in a randomized double-blinded manner.

Detailed description

Although evidence suggests that dopaminergic systems are involved in pain processing, the efficacy of dopaminergic interventions in reducing pain remains questionable. This randomized, double blinded, placebo-controlled, cross-over study was aimed to explore the effect of the dopamine agonist apomorphine on spontaneous pain intensity and evoked cold clinical and experimental pain in patients with lumbar radicular neuropathic pain (NP). Data was collected from 35 patients (18 men, mean age 56.2±13.1 years). The following five pain measures were tested before (baseline) and 30, 75 and 120 min subsequent to subcutaneous injection of 1.5 mg apomorphine or placebo in two separate sessions: spontaneous pain intensity, threshold and tolerance to cold pain in the most painful site in the affected leg and in a remote healthy site in the dominant hand.

Interventions

DRUGApomorphine

DRUGNormal Saline

Study design

Allocation

RANDOMIZED

Intervention model

CROSSOVER

Primary purpose

TREATMENT

Masking

TRIPLE (Subject, Investigator, Outcomes Assessor)

Eligibility

Sex/Gender

ALL

Age

18 Years to No maximum

Healthy volunteers

Inclusion criteria

1. Presence of radicular pain for at least 3 months; 2. Average pain level during the last week prior to enrollment \> 40 (0-100); 3. No use of a new analgesic drug within 30 days prior to entry to the study and 4. Adults who were capable of understanding the purpose and instructions of the study and signing an informed consent.

Exclusion criteria

1. Pregnancy or breastfeeding; 2. Presence of Parkinson's disease or any other extra-pyramidal diseases; 3. History of allergy to the investigational drugs: Apomorphine or Domperidone; 4. History of polyneuropathy and 5. Respiratory depression, dementia, psychotic diseases or hepatic insufficiency

Design outcomes

Primary

Measure	Time frame
Experimental and clinical cold pain tolerance measured in seconds	Up to 120 minutes after drug administration

Secondary

Measure	Time frame
Spontaneous clinical pain intensity measured on a numeric pain scale (NPS, 0-100)	Up to 120 minutes after drug administration
Experimental and clinical cold pain threshold measured in seconds	Up to 120 minutes after drug administration

Countries

Israel

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026