The hypothesis of the study is that sub-dissociative dose ketamine will prove to be superior to or as standard therapy, ketorolac, in the treatment of acute tension type headache (TTH) as measured by the 10 point Numerical Rating Scale (NRS. The aim of the study is to compare the safety & efficacy of intravenous sub-dissociative dose ketamine versus ketorolac for acute treatment of migraines in the Emergency Department (ED) The primary endpoints are: Patient perception of pain as described by the use the Numerical Rating Scale (NRS) at 30 minutes.

The secondary endpoints are: Frequency and mean dose of rescue/additional doses of therapy at 15, 30, 45, 60, 75, 90 min, Number of emergency department re-visits for acute migraine one month post discharge, incidence of dissociative effects (characterized by hallucination, disorientation, confusion, agitation, delirium, dreams) during study period, incidence of nausea, vomiting, or worsening headache, Incidence of bad taste, Incidence of burning sensations in the nostrils, incidence of hypertension, time to patient discharge from the initiation of study medication/placebo, patient satisfaction of pain control based on a Likert Scale.

This will be a "double-dummy" study in that there will be no placebo only arm. Medications will be administered in a double blind randomized fashion. Patients would be enrolled in Arm A or Arm B depending upon the initial randomization. Arm A would include 0.3 mg/kg ketamine into a 100 cc normal saline IV bag and normal saline injection (1ml) while Arm B would receive 100cc of normal saline and 30mg of ketorolac intravenously.

An order would be placed by the medical resident, medical attending, a study investigator who is a physician, or a pharmacist under the permission of the attending physician into Allscripts for a study intervention. Upon receiving the order in Allscripts, the order would be verified by the pharmacy. All medications will be prepared in pharmacy, which will maintain a master list of contents of each sealed envelope. Once notified of which envelope has been pulled, the pharmacist will prepare either arm. ED personnel will obtain the infusion preparation from pharmacy. It will be labeled for the patient, with study number, but without other identifying marks. When the study medication is picked up, pharmacy will open the sealed envelope to confirm which medication arm was prepared in order to internally verify the correct preparation. The nurse assigned to the patient would administer the intervention. A research associate or a study investigator would approach the patient to assess and record primary outcomes, secondary outcomes at designed time intervals. The data will be recorded on the data collection instrument. If additional medication is requested by the patient, the orders would be placed by the medical resident or attending who are assigned to the patient in the ED. Upon completion of the treatment portion of the study, patients will be asked of the participant's satisfaction with therapy. Only the patient who signed the consent form will be allowed to answer the questions.

All data retrieved from the paper data collection sheets will be transcribed into an encrypted and password protected electronic database by the research associate. All patient identifiers would be de-identified in the database. All participants would be assigned a study participant number.

Inclusion Criteria:

• The inclusion criteria are: Patients 18-65 years old who provides informed consent and presents to the ED with an acute tension type headache (TTH), as classified by meeting the following:

  1. Have at least 10 episodes of headache occurring on average less than 12 days per year AND Fullfuling B-D B. Lasting 30mins to 7 days C. At least 2 of the following 4 criteria
  1. bilateral location
  2. pressing/tightening (non-pulsating)
  3. mild or moderate
  4. not aggravated by routine physical activity such as walking or climbing stairs D. Both of the following
  1. no nausea/vomiting
  2. No more than one of photophobia or phonophobia

Exclusion Criteria: Non migraine primary headache disorder or unclassifiable, previous enrollment in study, fever >100.3, Patients with suspected secondary headache disorder such as SAH or sinusitis, performance of lumbar puncture or potential need for LP, Severe hypertension (≥180/100), History of CAD or hypertension, presence of/suspected for traumatic head injury in the past 30 days with or without loss of consciousness, Presence of/suspected for myocardial ischemia, presence of/suspected for alcohol intoxication, Hemodynamic instability, history of psychiatric disorders, known or suspected pregnancy or breast feeding, allergy to ketamine, ketorolac, previous enrollment in the study, patients with language barriers, refusal to provide consent to receive intravenous therapy, reported illicit drug use within the past 5 days, patients weighing over 100kg

Aside from primary investigator (B.Sin) and pharmacist procuring the study interventions, blinding will be applied to patient, physicians, nurses, research associates responsible for collect data and also the independent biostatistician responsible for evaluating the data. Patients will be randomized to receive study numbers that corresponds to treatment arms.