Hyland's teething tablets: our son became frightenly dazed and groggy

After reading many accounts online of very positive results parents had using teething tablets, I decided to give them a try this weekend. Around 5PM we gave our 9 month old 1 tablet (the instructions say 2 or 3). After 20 minutes I could see no side effects but also he didn't seem to have any relief and was still very fussy and crying some. So I then gave him 2 more for a total of 3 tablets.

We then went to a nearby park for a picnic. It was overcast but pretty hot and humid. Over the course of the next hour he became increasingly groggy, dazed, heavy eyes, and just really drugged looking.

We were very scared that the tablets were to blame and we quickly have him a cup of juice which he attacked as soon as he saw it.

We rushed him home and called our pediatrician and 20 minutes after drinking juice and being indoors he was himself again, playing, crawling, pulling up, and laughing.

In retrospect, I think its very possible he just got low on fluids in the heat and that was solely to blame but I wanted start this discussion to find out if any other parents have experienced this after giving their baby Hyland's teething tablets with Belladonna?