In a human heat-capsaicin-induced pain model, Indantadol HCl at a dose of 500 mg effectively reduced the area of secondary hyperalgesia to 67%. Indantadol HCl undergoes extensive liver metabolism, withthe formation of two major metabolites - CHF-3567 and 2-aminoindane. The drug is excreted in urine partially as the parent compound, but mostly as CHF-3567. The tolerability profile of Indantadol HCl at single doses up to 600 mg and twice-daily doses up to 400 mg in clinical trials was significantly more favorable than for other NMDA antagonists. Most side effects have been observed to be mild, and include dizziness and asthenia. Indantadol HCl is currently in phase II clinical trials in patients with diabetic peripheral neuropathic pain.[1]