What side effects are associated with this type of intervention?

The most common treatments for rattlesnake bites, such as ketamine and fentanyl, have several known side effects. Ketamine can cause dizziness, impaired gait, nasal discomfort, disorientation, restlessness, dissociation, delirium, psychosis, nausea, vomiting, and increased blood pressure. Fentanyl is associated with respiratory depression, constipation, nausea, vomiting, dizziness, and sedation. These side effects should be carefully considered when choosing a treatment plan.

What prior FDA approvals exist?

The FDA has approved antivenom as the primary treatment for rattlesnake bites, which neutralizes the venom's effects. For pain management, opioids like fentanyl, an opioid receptor agonist, are commonly used due to their potent analgesic properties. Ketamine, an NMDA receptor antagonist, is also used for its effective pain relief and minimal respiratory depression. Both drugs are part of standard practice for managing acute pain following rattlesnake envenomation, although specific FDA approvals for their use in this context are part of broader pain management guidelines rather than targeted approvals for snake bites.

What other types of research exist?

A promising novel alternative for pain management in rattlesnake bite patients is SLL-627, a highly selective and potent κ Opioid Receptor (KOR) agonist. SLL-627 has shown low liability to conditioned place aversion and does not reduce locomotor activity, which is a common side effect of other KOR agonists. This makes it a potential candidate for effective pain relief without the sedative effects typically associated with KOR agonists.

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Opioid Analgesic

Ketamine vs Fentanyl for Rattlesnake Bite Pain

Phase 4

Waitlist Available

Led By Meghan Spyres, MD

Research Sponsored by Meghan Spyres

Eligibility Criteria Checklist

Specific guidelines that determine who can or cannot participate in a clinical trial

Must have

Ages ≥ 18 years.

RSE requiring IV pain medication for NRS pain score > 5.

Must not have

On buprenorphine therapy.

History of uncontrolled hypertension

Timeline

Screening 3 weeks

Treatment Varies

Follow Up 30-120 minutes after drug administration

Awards & highlights

Pivotal Trial

Drug Has Already Been Approved

No Placebo-Only Group

Summary

This trial compares ketamine and fentanyl for managing severe pain in patients bitten by rattlesnakes. Ketamine blocks pain signals without addiction risk, while fentanyl reduces pain but can be addictive. Ketamine has been increasingly used in clinical studies to minimize acute postoperative pain and reduce opioid requirements.

Who is the study for?

This trial is for adults over 18 who've been bitten by a rattlesnake, need IV pain medication, and can consent to the study. They must not be allergic to ketamine or fentanyl, pregnant, have schizophrenia, uncontrolled high blood pressure, increased brain pressure or be intoxicated.

What is being tested?

The study tests how effective a single dose of ketamine compares with fentanyl in managing pain after a rattlesnake bite. Patients will report their pain levels following treatment at Banner - University Medical Center Phoenix.

What are the potential side effects?

Ketamine may cause changes in blood pressure, dizziness, nausea, disorientation or hallucinations. Fentanyl can lead to drowsiness, nausea, constipation or respiratory depression.

Eligibility Criteria

Inclusion Criteria

You may be eligible if you check “Yes” for the criteria below

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I am 18 years old or older.

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I need IV pain medication for severe pain.

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I was bitten or stung by a venomous creature less than 24 hours ago.

Exclusion Criteria

You may be eligible for the trial if you check “No” for criteria below:

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I am currently taking buprenorphine.

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I have high blood pressure that isn't well-controlled.

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I have high pressure inside my skull.

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I have been poisoned by a bite or sting.

Timeline

Screening ~ 3 weeks3 visits

Treatment ~ Varies

Follow Up ~ 30-120 minutes after drug administration

Screening ~ 3 weeks

Treatment ~ Varies

Follow Up ~30-120 minutes after drug administration

This trial's timeline: 3 weeks for screening, Varies for treatment, and 30-120 minutes after drug administration for reporting.

Treatment Details

Study Objectives

Study objectives can provide a clearer picture of what you can expect from a treatment.

Primary study objectives

Change in Pain Assessment Post Medication

Secondary study objectives

Adverse Events

Awards & Highlights

Pivotal Trial

The final step before approval, pivotal trials feature drugs that have already shown basic safety & efficacy.

Drug Has Already Been Approved

The FDA has already approved this drug, and is just seeking more data.

No Placebo-Only Group

All patients enrolled in this study will receive some form of active treatment.

Trial Design

2Treatment groups

Experimental Treatment

Active Control

Group I: KetamineExperimental Treatment1 Intervention

Drug administration: A single dose of ketamine 0.3 mg/kg IV over 15 minutes. Time drug given will be documented Data obtained prior to med administration and then following medication administration at intervals of 15, 30, 60 and 120 minutes * Record vital signs (HR, B/P, resp rate, O2 sat) * Obtain and assess pain response scores 1. Pain Numerical Rating Score (NRS - 0-10) 2. Richmond Agitation Sedation Scale (RASS) 3. Side Effect Rating Scale for Dissociative Anesthesia (SERSDA) * Record any airway interventions required? If yes what? new supplemental O2/BVM/intubation, jaw thrust * Record any rescue meds, dose and time (Rescue medication - Fentanyl): * 1 mcg/kg IV fentanyl (0.5 mcg/kg if age \>55 yrs) * Defined as rescue if given \<30 min post study intervention for pain score \>5 or patient requesting additional medication. * Patient pain satisfaction score at discharge

Group II: FentanylActive Control1 Intervention

Drug administration: A single dose of fentanyl 1mcg/kg IV, maximum 100 mcg, over 15 minutes. Time drug given will be documented Data obtained prior to med administration and then following medication administration at intervals of 15, 30, 60 and 120 minutes * Record vital signs (HR, B/P, resp rate, O2 sat) * Obtain and assess pain response scores 1. Pain Numerical Rating Score (NRS - 0-10) 2. Richmond Agitation Sedation Scale (RASS) 3. Side Effect Rating Scale for Dissociative Anesthesia (SERSDA) * Record any airway interventions required? If yes what? new supplemental O2/BVM/intubation, jaw thrust * Record any rescue meds, dose and time (Rescue medication - Fentanyl): * 1 mcg/kg IV fentanyl (0.5 mcg/kg if age \>55 yrs) * Defined as rescue if given \<30 min post study intervention for pain score \>5 or patient requesting additional medication. * Patient pain satisfaction score at discharge

Treatment

First Studied

Drug Approval Stage

How many patients have taken this drug

Ketamine

2011

Completed Phase 4

~1120

0 / 7Eligibility criteria met

Research Highlights

Information in this section is not a recommendation. We encourage patients to speak with their healthcare team when evaluating any treatment decision.

Mechanism Of Action

Side Effect Profile

Prior Approvals

Other Research

The most common treatments for rattlesnake bites include ketamine and fentanyl. Ketamine, an NMDA receptor antagonist, reduces pain by blocking the excitatory neurotransmitter glutamate, preventing pain signal transmission. Fentanyl, an opioid receptor agonist, binds to mu-opioid receptors, inhibiting pain neurotransmitter release and providing analgesia. These treatments are vital for managing the severe pain from rattlesnake envenomation, with ketamine also helping to reduce the need for high opioid doses, thereby minimizing opioid-related side effects and dependency.

MK-801 blocks dynorphin A (1-13)-induced loss of the tail-flick reflex in the rat.A dose-ratio comparison of mu and kappa agonists in formalin and thermal pain.Evaluation of the interaction of mu and kappa opioid agonists on locomotor behavior in the horse.