That is really interesting MissA as I googled your tablets and realised I remembered it as Phenergen.
I am old enough to remember when Phenergen was sold over the counter as a syrup and " slightly unscrupulous mothers" would give it to babies and young children to knock them out if they were poor sleepers or if they wanted to ensure they stayed asleep.
It was viewed rather badly and I thought it had been taken off the market years ago.
Baby Reindeer - anyone watched it?
Alphabetical girls and boys names January 2024