I use anti-histamines for hayfever. This summer I moved house, so my hayfever was a lot worse, and went on for a lot longer. I was taking Loratadine tablets every day.
I felt like absolute carp, and didn’t know why. Generally really tired and had really bad guts (proper green apple splatters 😮 ).
By chance, a packet of tablets ran out so I started a new one which the missus had bought; they were cetirizine hydrochloride. Within a day I felt much better and my guts cleared right up.
Not sure if it was the long termness, or the specific tablet. Never noticed a problem with Loratadine before.
Really looking forward to next years pollen season 😕
Dave