A teleconference meeting of the National Drug Scheduling Advisory Committee was held beginning at 1:00 pm EST on Monday, August 12, 2002.  The purpose of the meeting was to review, at the request of the Executive Committee, the scheduling recommendation made by the Committee at the June 1-2, 2002 meeting regarding dextromethorphan.  This request had been made in response to an inquiry from McNeil Consumer Healthcare.

Participants

NDSAC members:                   Dr. Marilyn Caughlin (Chairman), Dr. Jeff Taylor (Vice-Chairman), Dawn Frail, Larry Lynd, and Dr. Colleen Metge

Note that Committee member Dr. Mark Armstrong was not included in this teleconference meeting, as he had not participated in the original decision taken at the June 1-2 2002 meeting.

Secretariat:                              Barbara Wells (NAPRA Executive Director)

Absent:                                    Phil Hudson, Joan Sayer

Dr. Caughlin called the meeting to order at 1:05 pm and referred participants to the correspondence and documents received from original submission sponsor Pfizer Canada, and Interested Party McNeil Consumer Healthcare.

The matter before the committee members was to confirm or reassess their previous scheduling recommendations for dextromethorphan, in light of information received pursuant to the meeting.  The recommendations were:

• Unscheduled status for: “Dextromethorphan (in liquid dosage form and in package sizes containing no more than 300mg)”, and
• retention of Schedule III status for “Dextromethorphan (in package sizes containing more than 300 mg or in dosage forms other than liquid).

McNeil was questioning the rationale for the dosage form and package size components of these decisions.  As directed by the Executive Committee, Dr. Caughlin instructed the committee to restrict the review to these two aspects only: the 300 mg ceiling and liquid dosage form for unscheduled status and suggested that they be dealt with individually.

300 mg package size

The Committee confirmed their decision to allow for package sizes containing up to 300 mg DM to be sold on an unscheduled basis, based on public safety.  This level would provide for 5 days of dosing for a child, while offering a total DM level considerably below that reported to be needed to produce euphoria (420 mg) for non-medical use by abusers.  Intervention by a health care professional would be warranted in cases where symptoms have not been alleviated after 5 days of treatment, due to the risk of misdiagnosis.

Liquid vs. solid dosage forms

There was considerable discussion about the evidence presented by McNeil regarding the potential for abuse offered by DM in solid oral dosage forms as compared to that of liquid oral dosage forms.  It was pointed out that in an expert opinion obtained by Pfizer, it had been suggested that the potential for abuse was greater in solids than in liquids (i.e. more feasible for abusers to consume large quantities of tablets to obtain euphoric effect than to consume the same drug content in liquid formulations), whereas the McNeil submission proposed that liquid dosage forms represented an equal or greater magnitude of abuse potential. 

After some debate on the dosage form aspect of the recommendation, the committee agreed that:

1.        dextromethorphan in both liquid and solid dosage forms in package sizes containing more than 300 mg should remain in Schedule III, as originally recommended, 

2.        there was sufficient evidence to confirm the original decision to allow for liquid dosage forms in package sizes containing up to and including 300 mg of dextromethorphan to be assigned Unscheduled status; and that

3.        further information would be requested from McNeil before completing the review of the decision regarding solid dosage forms of dextromethorphan.  It was also agreed that this specific review should be conducted as expeditiously as possible.

To be reported to the NAPRA Executive Committee. 

The meeting concluded at 2:25 pm.