This should be possible. First, stop the Tridion Content Manager Search Indexer service.
Then open a 64 bit PowerShell console run as Administrator user and execute the commands as shown below:
Copyright (C) 2013 Microsoft Corporation. All rights reserved.
PS C:\> Import-Module Tridion.ContentManager.Automation
PS C:\> Remove-TcmQueueMessages SearchQueue
Are you sure you want to perform this action?
Performing the operation "Remove-TcmQueueMessages" on target "SearchQueue".
[Y] Yes [A] Yes to All [N] No [L] No to All [S] Suspend [?] Help (default is "Y"): Y
After the queue has been purged, you can restart the Search Indexer service.