Safety, tolerability and pharmacokinetics of the N-methyl-D-aspartate antagonist Ro-01-6794/706 in patients with acute ischemic stroke. The Dextrorphan Study Group and Hoffmann-La Roche.

Dextrorphan HCl (Ro 01-6794/706) is an NMDA receptor antagonist with clinical potential for administration in an elderly population of acute ischemic stroke patients. In vivo experience with such patients demonstrated a consistent pharmacologic effect/adverse experience profile that is typical of an NMDA receptor antagonist (e.g., nystagmus, nausea, vomiting, agitation, somnolence, hallucinations and hypertension). For the most part, these pharmacologic effects were mild to moderate in severity; short-lived; reversible; not life-threatening and subjectively tolerated. The most serious pharmacologic effect produced by dextrorphan administration was hypotension, which occurred within a well-defined window of 90 minutes from the start of the loading dose infusion in patients who received 200 mg/hr or greater loading dose infusions. In all cases it was reversible without neurologic sequelae. Careful review of demographic and pharmacokinetic parameters did not demonstrate any overriding factor(s) to the production of hypotension other than the rate of the loading dose infusion. Severe hypotension, severe decreased levels of consciousness and respiratory depression should not be generally expected at loading doses less than 200 mg/hr. In summary, dextrorphan can be safely given to an elderly population of ischemic stroke patients as a loading dose rate below 200 mg/hr and as a maintenance dose rate between 50-90 mg/hr for 24 hours when patients are monitored carefully for pharmacologic effects.