Glucagon's Cardiovascular Effects With and Without Beta-blocker-induced Cardioinhibition

Study Overview
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Brief Summary
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This trial investigates effects of a glucagon bolus injection on heart rate, blood pressure and cardiac output during beta-blocker-induced cardiodepression. Furthermore, the effects of two different doses of intravenous glucagon on hemodynamic parameters are explored.

Detailed Description
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This trial investigates effects of a glucagon bolus injection on heart rate, blood pressure and cardiac output during beta-blocker-induced cardiodepression. Furthermore, the effects of two different doses of intravenous glucagon on hemodynamic parameters are explored. Glucagon, administered as a 50 micrograms/kg bolus injection which can be repeated or followed by continuous infusion (50 -150 micrograms / kg / hour) is a well-accepted and recommended treatment of beta-blocker poisoned patients [1-4]. The evidence for the recommended glucagon dose is based on animal trials and human case studies suggesting beneficial effects. Theoretically, high-dose glucagon mimics effect of beta-receptor agonists (increasing heart rate and cardiac output) [5] via activation of cardiac glucagon receptors, which cannot be blocked by beta blockers [1,6]. Glucagon receptors in the heart muscle are seemingly activated only at high glucagon levels [7] (but could also theoretically be an off-target effect); therefore the recommended glucagon dose for beta-blocker poisonings is higher than that recommended for reversal of hypoglycemia. Despite some animal and human case data suggesting beneficial effects of glucagon, other data suggest that glucagon may actually be inferior to other therapies of cardiovascular collapse due to cardioinhibitory drug poisonings [2]. It is important to keep in mind that the knowledge about glucagon's effects in poisoning situations is derived from uncontrolled cohort studies and case reports as well as animal studies [3,8]. Thus, the recommended dose has never been studied in a controlled clinical trial in humans. Therefore, the overall level of evidence pertaining to glucagon in the management of beta-blocker overdoses is low. There is a need for clinical human data investigating the glucagon doses recommended for treatment of beta-blocker overdose. The purpose of this participant- and outcome assessor blinded, randomized placebo-controlled crossover clinical trial is to investigate the effects of intravenous glucagon on the circulation alone or during beta-blocker-induced heart (rate) suppression. The trial includes a total of six visits; a screening visit and five trial days as described under Arms and Interventions. At the screening visit, anthropometric data (weight, height, blood pressure and pulse) is measured. Additionally, blood samples are collected in accordance with in/exclusion criteria. A spot urine sample measuring the albumin/creatinine ratio is collected and an electrocardiogram (ECG) is recorded to verify normality of heart rhythm and electrical impulses. In addition, an investigator carries out a clinical examination. Based on the clinical examination, urine and blood tests and ECG measurement, an investigator assesses whether the trial participant meet all inclusion criteria and no exclusion criteria. After screening and inclusion, participants will be invited to five trial days at the trial site (days A-E). The participant is blinded to interventions. On each day, participants are required to be fasting for 8±2 hours. A peripheral venous line is inserted into each antecubital vein. An arterial catheter connected to a pressure transducer is inserted into the radial artery in the wrist. In randomized order, one of the five interventions are performed (see below). A 5 lead ECG connected to a computer is placed on the participant. At T=-15 minutes, esmolol intravenous solution (10 mg esmolol/ml esmolol hydrochloride) or matching placebo is administered as a loading dose at baseline (time= -15 min) (corresponding to 1,25 mg/kg/min esmolol) [9]. Continuous infusion (500-750 micrograms/kg/min) of esmolol/placebo is then administered until T=30 minutes. Infusion is halted if heart rate decreases below 30 bpm or >25% from baseline, the systolic blood pressure drops below 80 mm Hg, or the participant experiences subjective side effects. Esmolol/placebo infusion stops at T=30 minutes. Glucagon (GlucaGen injectable solution) or saline solution is administered at time=0 minutes as an intravenous bolus (50 micrograms /kg over 1-2 minutes) on days C & E or as a continuous infusion (50 micrograms/kg over 30 min on day D). One point five grams of acetaminophen administered as a disintegrating tablet dissolved in 100 ml of water with guar gum is given orally shortly before study start on each day [10]. Repeated ECG's are recorded and blood is drawn for measurements of secondary biochemical endpoints. A drop of blood is used to test glucose levels using a blood glucose meter. Cardiovascular parameters (heart rate, blood pressure and pulse contour curve/arterial pressure wave) are recorded via the arterial catheter and pressure transducer connected to a computer. The participant is closely monitored on site until T=60 minutes.

Official Title
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A Randomized, Participant-blinded Five-arm Crossover Study With Blinded Outcome Assessment Investigating Glucagon's Cardiovascular Effects With and Without Beta-blocker-induced Cardioinhibition.

Conditions
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Drug Overdose, Overdose of Beta-adrenergic Blocking Drug

Intervention / Treatment
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* Drug: Glucagon
* Drug: Esmolol
* Drug: Physiologic saline - glucagon dummy
* Drug: Physiologic saline - esmolol dummy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy male determined by investigator, based upon physical examination, medical history, ECG, vital signs and laboratory results Body mass index (BMI) ≥ 18.5 and ≤ 29.9 kg/m2 and body weight between 50 and 100 kg, inclusive, at screening visit. Exclusion Criteria: Abnormal blood levels of sodium, potassium, creatinine, alanine transaminase (ALT), alkaline phosphatase, albumin, bilirubin, hemoglobin, HbA1c, cholesterol fractions. Bradycardia (<45 beats per minute) Hypotension (systolic blood pressure < 100 mmHg) Second or third degree atrioventricular conduction delay Sick sinus syndrome Any heart disease or hypertension Pheochromocytoma Allergy to any active or inactive ingredient contained in investigatory medicines or tools. Raynaud's syndrome Prinzmetal's angina Diabetes Pulmonary disease Pheochromocytoma Any contraindication against investigatory medicines or tools.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 40 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: 5-arm, participant and outcome-assessor blinded, randomized, placebo-controlled study.
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Esmolol-placebo+glucagon 1 placebo (A)<br>Physiologic saline - esmolol dummy (10 mg esmolol/ml) is administered as a loading dose at baseline (time= -15 minutes) (corresponding to 0.125 ml/kg/min of saline). Continuous infusion (0.05-0.075 ml/kg/min) of saline is then administered until T=30 minutes. + Physiologic saline - glucagon dummy bolus 50 ml at time=0. | Drug: Physiologic saline - glucagon dummy<br>* Isotonic 0.9 % sodium chloride solution is administered as matching placebo to glucagon, and injected in identical rates on corresponding days.<br>* Other names: normal saline;Drug: Physiologic saline - esmolol dummy<br>* Isotonic 0.9 % sodium chloride solution is administered as matching placebo to esmolol, and injected in identical rates on corresponding days.<br>* Other names: normal saline;|
| Experimental: Esmolol+glucagon 1 placebo (B)<br>Esmolol intravenous solution (10 mg/ml esmolol hydrochloride) is administered as a loading dose (1.25 mg/kg/min esmolol) at baseline (time= -15 minutes). Continuous infusion (500-750 micrograms/kg/min) of esmolol/placebo is then administered until T=30 minutes. + Physiologic saline - glucagon dummy bolus (50 ml) at time=0. | Drug: Esmolol<br>* Esmolol hydrochloride 10 mg/ml is infused from time -15 min to time + 30 minutes as an initial bolus followed by an infusion. infusion rate is tapered if heart rate declines below 30 beats per minute (bpm) or >25 % from baseline, systolic blood pressure decreases below 80 mmHg or the participant experiences side effects.<br>* Other names: ATC C07AB09;Drug: Physiologic saline - glucagon dummy<br>* Isotonic 0.9 % sodium chloride solution is administered as matching placebo to glucagon, and injected in identical rates on corresponding days.<br>* Other names: normal saline;|
| Experimental: Esmolol+glucagon 1 (C)<br>Esmolol intravenous solution (10 mg/ml esmolol hydrochloride) is administered as a loading dose (1.25 mg/kg/min esmolol) at baseline (time= -15 minutes). Continuous infusion (500-750 micrograms/kg/min) of esmolol/placebo is then administered until T=30 minutes. +Glukagon 1 (50 μg/kg bolus - over 1-3 min from time=0 min in 50 ml isotonic fluid) | Drug: Glucagon<br>* Glucagon 1 mg/ml solution is dissolved in 50 ml isotonic fluid and injected as bolus corresponding to 50 micrograms/kg over 1-3 minutes from time=0 on day C+E. on day D (glucagon 2), 50 micrograms/kg of glucagon is infused over 30 minutes from time=0 to time =30.<br>* Other names: ATC H04AA01;Drug: Esmolol<br>* Esmolol hydrochloride 10 mg/ml is infused from time -15 min to time + 30 minutes as an initial bolus followed by an infusion. infusion rate is tapered if heart rate declines below 30 beats per minute (bpm) or >25 % from baseline, systolic blood pressure decreases below 80 mmHg or the participant experiences side effects.<br>* Other names: ATC C07AB09;|
| Experimental: Esmolol-placebo+glucagon 2 (D)<br>Physiologic saline - esmolol dummy (10 mg esmolol/ml) is administered as a loading dose at baseline (time= -15 minutes) (corresponding to 0.125 ml/kg/min of saline). Continuous infusion (0.05-0.075 ml/kg/min) of saline is then administered until T=30 minutes. +Glukagon 2 (50 μg/kg bolus - over 30 min in 50 ml isotonic fluid from time=0 min) | Drug: Glucagon<br>* Glucagon 1 mg/ml solution is dissolved in 50 ml isotonic fluid and injected as bolus corresponding to 50 micrograms/kg over 1-3 minutes from time=0 on day C+E. on day D (glucagon 2), 50 micrograms/kg of glucagon is infused over 30 minutes from time=0 to time =30.<br>* Other names: ATC H04AA01;Drug: Physiologic saline - esmolol dummy<br>* Isotonic 0.9 % sodium chloride solution is administered as matching placebo to esmolol, and injected in identical rates on corresponding days.<br>* Other names: normal saline;|
| Experimental: Esmolol-placebo+glucagon 1 (E)<br>Physiologic saline - esmolol dummy (10 mg esmolol/ml) is administered as a loading dose at baseline (time= -15 minutes) (corresponding to 0.125 ml/kg/min of saline). Continuous infusion (0.05-0.075 ml/kg/min) of saline is then administered until T=30 minutes. + Glukagon 1 (50 μg/kg bolus - over 1-3 min from time=0 min in 50 ml isotonic fluid) | Drug: Glucagon<br>* Glucagon 1 mg/ml solution is dissolved in 50 ml isotonic fluid and injected as bolus corresponding to 50 micrograms/kg over 1-3 minutes from time=0 on day C+E. on day D (glucagon 2), 50 micrograms/kg of glucagon is infused over 30 minutes from time=0 to time =30.<br>* Other names: ATC H04AA01;Drug: Physiologic saline - esmolol dummy<br>* Isotonic 0.9 % sodium chloride solution is administered as matching placebo to esmolol, and injected in identical rates on corresponding days.<br>* Other names: normal saline;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Heart rates on the esmolol+glucagon-day compared to the esmolol+placebo-day (2 minute average) | Arterial catheter connected to a pressure transducer records heart rate (beats per minute). | Glucagon bolus + 5±1 minute | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in heart rate from baseline compared between study days. | Arterial catheter connected to a pressure transducer records heart rate (beats per minute). | -20, -10, 0, glucagon+3, +5, +10, +15, +20, +30, +40, +50, +60 minutes | 
| Change in stroke volume (ml) from baseline compared between study days. | Stroke volume (ml) derived from arterial pulse contour analysis. | -20, -10, 0, glucagon+3, +5, +10, +15, +20, +30, +40, +50, +60 minutes | 
| Change in systolic, diastolic and mean arterial pressure (mmHg) from baseline compared between study days. | Arterial catheter connected to a pressure transducer records blood pressure in mm Hg. | -20, -10, 0, glucagon+3, +5, +10, +15, +20, +30, +40, +50, +60 minutes | 
| Glucagon pharmacokinetics | Blood samples drawn for measurements of plasma glucagon | Baseline and glucagon +2, +4, +6, +10, +15, +20, +30, +40, +50, +60 minutes | 
| Effects of glucagon on blood glucose compared to placebo | Full blood glucose measured with a blood glucose meter | Baseline and glucagon +2, +4, +6, +10, +15, +20, +30, +40, +50, +60 minutes | 
| Adverse effects of glucagon | Nausea rated by a 4-point, verbal description scale (VDS) (no nausea=0, mild=1, moderate=2, severe=3). | Baseline and glucagon +6,+10, +30, +60 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Glucagon, Beta-adrenergic antagonist, poisoning