Overview

BACKGROUND AND PURPOSE Outpatient surgery (day case surgery) is increasing. When the patients go home on the same day, this demands safe pain relief. A reduction of morphine (opioid) use is sought because of side effects and the dependency risk. An effective alternative to opioids is ketamine, which lacks the side effects of opioids but provides powerful analgesic effects.

METHOD At the start of surgery, Ketamine or placebo will be given in a vein to evaluate if the acute pain decreases significantly. Inflammation is known to cause pain. By measuring different proteins in the blood, the investigators want to understand how inflammation links to the pain. Wisdom tooth surgery provides significant post-operative pain and is a widely accepted pain model in drug studies. Patients referred for wisdom tooth surgery are asked to participate in the study. For statistical certainty, in total 165 persons will be enrolled to three groups. Two with active drug (different dose) and one placebo. Everyone gets local anesthesia. The completion of the study will be done in four years. The Ethics Review Board has approved the study.

CLINICAL RELEVANCE Effective pain relief after daily surgical procedures is important for patients safety and reducing the risk of long-term pain. It is also ethically necessary for the continued expansion of day case surgery. New knowledge of the mechanisms of pain increases the opportunities for individual and safe pain relief. Day case surgery is performed in all operating specialties, this might affects many patients nationally and internationally.

Eligibility

Inclusion Criteria:

• Healthy or mild well-compensated systemic disease (ASA I & II)
• 18- <45 years
• 50-100 kg body weight

Exclusion Criteria:

• Medication drugs: analgesics, hypnotics (the last week before surgery), thyroid hormones, psychoactive drugs or monoamine oxidase inhibitors (MAO inhibitors).
• Hypertension [> 150/95 mmHg in screening study]
• Heart failure
• Psychosis
• Epilepsy
• Hyperthyreosis
• Myasthenia gravis
• Glaucoma
• Verified sleep apnea
• Diabetes (insulin treated)
• Porphyria
• Pregnancy
• Breast-feeding
• Blood transmitted infections, such as HIV and hepatitis B and C
• Known hypersensitivity to midazolam, ketamine, ibuprofen, or local anesthetics
• Inability to obtain the requisite written or oral information