NMDA antagonists
| Drug and Dose | Method | Comment | References |
|---|---|---|---|
| Dextromethorphan | |||
| 150 mg oral | Pressure stimulation and von Frey hair stimulation to the skin near surgical incision in 50 patients scheduled for elective abdominal hysterectomy. | No significant effects. | Ilkjaer et al. (2000) |
| 60 or 90 mg oral | Repeated stimulation by thermal pulses applied to the skin or by mechanical stimuli to the muscle in 14 patients with fibromyalgia. | Thermal and mechanical repeated stimulations were reduced by both doses, 90 mg being most effective. | Staud et al. (2005) |
| Ketamine | |||
| 30-min (0.3 mg/kg i.v.) | Pressure, intramuscular, and cutaneous electrical stimulation. The pain intensity during experimental muscle pain by intramuscular hypertonic saline was also recorded in 17 patients with whiplash-associated disorder. | No significant effects in any of the tests. | Lemming et al. (2005) |
| 0.3 mg/kg i.v. | Pressure pain stimulation at tender points and control points in 11 patients with fibromyalgia. | Pressure pain thresholds and pain tolerances at tender points and control points increased. | Sörensen et al. (1995) |
| 0.3 mg/kg i.v. | Pressure pain stimulation at tender and nontender point areas in 18 patients with fibromyalgia. | Patients were classified as responders or nonresponders according to clinical pain intensity ratings taken before, during, and after the tests. Pressure pain and tolerance thresholds increased significantly in responders but not in nonresponders | Sörensen et al. (1997) |
| Seven 5-min low-dose i.v. infusions with increasing doses at 20-min intervals | Skin heat pain stimulation in 10 patients suffering from chronic complex regional pain syndrome type 1. | A dose-dependent anti-nociceptive effect to skin heat stimuli was observed. This effect ended immediately after termination of the infusion. | Sigtermans et al. (2010) |
| 0.55 mg i.v. | Tactile, pinprick, and pressure pain stimulation at 11 sites around the temporomandibular joint in 18 patients with temporomandibular joint arthralgia. | No significant effects in any of the tests. | Ayesh et al. (2008) |
| 0.15 mg/kg i.v. | Brush (allodynia), repeatedly pricking the affected skin area, tactile, and thermal stimulations of the skin were examined in eight patients with postherpetic neuralgia. | No significant changes in thermal pain thresholds or tactile sensations were observed. Allodynia and pain evoked by repeatedly pricking the affected skin area were significantly decreased. | Eide et al. (1994) |
| 0.24 mg/kg as 30 min infusion | Brush and repetitive pinprick stimuli of the skin, and stimulation by acetone drop on the allodynic skin in 20 patients with nerve injury pain. | Evoked pain to brush and repetitive pinprick was reduced. Acetone-induced cold allodynia was unchanged. | Gottrup et al. (2006) |
| 0.3 mg/kg over 30 min | Intramuscular infusion of hypertonic saline into the anterior tibial muscle as well as intramuscular electrical stimulation (single and repeated), muscle pressure, and cutaneous electrical stimulations were performed in 15 patients with fibromyalgia. | Pain from hypertonic saline was reduced. Local and referred pain areas were reduced. No differences in response to single electrical stimulation but temporal summation to intramuscular and cutaneous electrical stimuli decreased. Muscle pressure pain tolerance threshold was increased, whereas pressure pain threshold was not affected. | Graven-Nielsen et al. (2000) |
| Bolus 60 μg/kg; infusion, 60 μg/kg/min (20 min) | Heat/cold stimulation and allodynia/hyperalgesia to heat/cold stimulation were determined inside the affected skin area and in a contralateral non-painful area in 12 patients with neuropathic pain. | No significant differences in detection thresholds but reduction in pain at threshold for cold pain. Hyperalgesia was reduced. | Jørum et al. (2003) |
| 50, 100, and 150 ng/ml i.v. | Thermal stimulations (cold and heat) and pinprick stimulation in the region of allodynia in 12 patients with neuropathic pain. | Cold threshold and cold pain thresholds increased. No effect on heat stimulation. Reduction in stroking and von Frey evoked allodynic area. | Leung et al. (2001) |
| 0.5 mg/kg | Electrical stimulations in 15 patients after abdominal hysterectomy. | Electric sensation, pain detection and tolerance thresholds increased. | Wilder-Smith et al. (1998) |
| (S)-Ketamine | |||
| 3-h infusion at 2 μg/kg/min | Pressure pain stimulation in five different dermatomes and the sum of pressure pain tolerances before, at end of, and after infusion were calculated for nine patients with chronic pancreatitis pain. | The sum of pressure pain tolerances at end of infusion was significantly higher than for placebo but returned to preinfusion values 1 h after end of infusion. | Bouwense et al. (2011) |