When treating allergies, drowsiness is often linked to antihistamines that you take to control a runny nose, sneezing, and itchy/red nose and eyes. So, why do antihistamines make you drowsy?

Histamines are chemicals secreted by the immune system to combat allergens. In that process, they cause symptoms such as a runny nose, sneezing, and red or itchy eyes. Antihistamine medicines offer relief from these symptoms by blocking the effects of histamine.

Histamine is also secreted in the brain, where it produces a feeling of wakefulness. And antihistamines used to treat allergies related histamine secretion can get into the brain, making you feel a bit drowsy.

On the other hand, few antihistamines are less likely to cause drowsiness than other allergy drugs. However, reactions vary from one person to another. For instance, what relieves your allergy symptoms without making you drowsy may work differently for your friend.

Second-generation antihistamines, such as Generic Zyrtec (cetirizine) and Generic Claritin (Loratadine), are often marketed as non-sedating or non-drowsy allergy medications. They, in fact, cause less drowsiness than first-generation antihistamines, such as chlorphenamine and diphenhydramine (Benadryl). Another added advantage of using a second-generation antihistamine such as Generic Zyrtec is that it lasts longer than older ones.

To prevent daytime drowsiness, you can take Generic Zyrtec in the evening rather than in the morning. Most physicians recommend taking the second-generation antihistamines before going to bed because may help you sleep well, with drowsy effects wearing down by the next day.

However, you should be aware of the fact that drowsiness may last longer than you might expect. Also, some antihistamines can cause disturbing or vivid dreams. More importantly, do not drink alcohol when you are taking Generic Zyrtec because it will increase the sedation or drowsiness.

Apart from allergy medication, many cold and flu medications available to treat a runny nose and sneezing usually include first- or second-generation antihistamines, which may cause more sedation. A combination of flu, cold and allergy medications treat cold or flu symptoms by drying up a runny nose than the newer ones.

Because of their drowsy effect, allergy medicines with antihistamines, including Generic Zyrtec, are labeled for bedtime use. You must take this labeling seriously because some combinational medications such as doxylamine are more sedating than others. More is never better. You must read labels carefully and take only as advised.

If your allergy symptoms do not subside or persist for more than two weeks even after using over-the-counter Generic Zyrtec medication, it is better to see a certified allergist for a full and proper diagnosis.

Antihistamines, such as Generic Zyrtec 100mg, are intended for symptomatic relief. If the allergy medication is causing side effects that make you extremely dizzy or drowsy, you can check with your doctor for alternatives.