The antihistamines or allergy drugs-are designed to stop allergic reactions by stopping the histamine, a neurotransmitter, from producing water in the body. They are most commonly used to stop hay fever symptoms.
But in working on the histamine, they can aggravate asthma. Other people at risk from the antihistamines, which include Piriton, Phenergan and Triludan, are epileptics and pregnant women as the drugs can bring on convulsions.
A more common reaction is drowsiness, as all the labels tell you-but some fail to point out that any drowsiness can come on only two to three hours later. Just to complicate matters, an almost equally common reaction can be the very opposite, and quite a few cases of stimulation, such as nervousness, excitement, tremors and sweating have also been reported.
Other reactions have included blurred vision, loss of appetite, vomiting, diarrhea, nausea, indigestion, and difficulties in passing water.