I've seen an interview recently where Mr and Mrs McCann were asked directly whether they used any medication to subdue the children and they categorically denied it.
The basis of this rumour I think stemmed from the twins being "unresponsive" when being woken up to what was essentially the middle of the night to them.
I believe forum carried a false narrative that Mr McCann had medical books by his bedside, along with books on how to commit the perfect murder and a bible open at a certain page which clearly indicated Kate had done something bad. In fact the amount of reading material they took on holiday according to some people was so enormous and varied, it is any wonder they managed to get out and do anything but read. Let alone get through customs with the alleged reading material they had.
I find it very hard to believe that Madeleine's parents would use medication to make their children sleep at night.To do so would selfish and very ruthless
Kate, indeed, had a Bible with a marked passage in it that referring to the death of a child, given to Kate by a friend who had, herself, marked the passage in response to a tragedy in her own family.
Gerry took a book with him on the holiday that was a fiction murder story, light, popular reading and in the best-seller fiction list at the time.
Gerry was in possession of 'top secret' CEOP manuals, freely available to download from the internet.
And much else besides ....