Low Dose Ketamine Versus Morphine for Moderate to Severe Pain in the Emergency Department

Inclusion Criteria:

1. ED patients18-55 years old presenting with moderate to severe (Numeric Pain Rating Score \>5) acute (less than 7 days)
2. abdominal, flank, back or musculoskeletal pain warranting (in the treating physician's judgment) administration of intravenous opioid pain medication.
3. Patients must be awake, alert and oriented to time, place and person,
4. patient must be able to demonstrate understanding of the informed consent.
5. Patient must be able to verbalize how much pain they are having on the 10 point Numeric Rating Pain Scale,
6. Patient mus be able to verbalize the nature of the side effects he may be experiencing from the intravenous analgesia.

Exclusion Criteria:

1. Pregnancy or breast feeding
2. SBP\<90
3. Weight greater than 115kg or less than 45kg,
4. altered mental status,
5. allergy to ketamine or morphine,
6. history of acute head or ocular trauma
7. presence of intracranial mass or vascular lesion, presence of psychiatric history
8. diagnosis or treatment (as assessed by electronic chart review).
9. history of seizure or intracranial hypertension
10. history of chronic pain, pain syndrome or fibromyalgia
11. presence of cardiovascular disease except controlled hypertension
12. history of acute head or ocular trauma, drug or alcohol abuse in the preceding 6 months
13. drugs or alcohol abuse in the preceding 6 months
14. SBP\>180
15. HR\<50
16. HR\>150
17. RR\<10
18. RR\>30
19. administration of opiate pain medication in the past 4 hours prior to assessment (i.e. home, EMS, triage, office, etc.)
20. presence of renal or hepatic insufficiency (as assessed by electronic chart review),