Antihistamines for Common Cold: Beneficial or Harmful?

A common cold is among the most harmless yet irritating ailment that attacks when you want to avoid it the most. A common cold is a viral infection, usually caused by a virus called rhinovirus. It affects children more commonly, and causes symptoms of sore throat, nasal stuffiness, runny nose or nasal discharge, and sneezing.

Though we all know that it is just a matter of a seven to ten days before we can be back to normal after a common cold, we often take medications to stop the sneezes and the runny nose to make us feel better.

Many of these medications are available over-the-counter. Some of these medications contain decongestants to reduce nasal congestion. Another common ingredient in cold medications is an antihistamine.

Antihistamines are of two main types – the older sedating antihistamines like diphenhydramine and chlorpheniramine and the newer less sedating or non-sedating types like cetirizine and loratadine. Antihistamines negate the effect of histamine, which is released in the body during an allergic reaction and causes symptoms like a runny nose and itching. Therefore, they are mainly effective in allergic reactions like hay fever.

The question then arises - Is an antihistamine drug really effective in common cold? Is its use associated with side effects? Researchers studied previously published papers on the topic to find out the same.

Researchers included a total of 18 studies that evaluated the use of only an antihistamine in the treatment of common cold, with symptoms of a stuffy or runny nose and sneezing, in adults as well as children. The antihistamines were administered either orally or intranasally and belonged either to the sedating or non-sedating groups. Each study also had a placebo group for comparison.

The researchers found that:

• Antihistamines produced a short-term benefit on the severity of overall symptoms which was noted on day 1 or 2 of symptoms. However, this benefit was not noted later, around 3 to 4 days or towards the end of the cold, around 6 to 10 days.
• With respect to individual symptoms of common cold like nasal congestion, runny nose and sneezing, some non-significant benefit was observed with sedating antihistamines on runny nose. Sedating antihistamines have a drying effect on the mucous membranes, which is unrelated to its antihistamine effect. This could explain the beneficial effects of these drugs on runny nose.
• Side effects like sedation were more common with sedating antihistamines though it was not clinically significant.
• Only two studies were conducted in children. Based on these studies, it is difficult to conclude that antihistamines are useful in children with common cold.

Based on the results of this study, the researchers feel that there is no adequate evidence to support the use of antihistamines for the treatment of common cold. Researchers conclude that antihistamines may not be so effective in treating common cold.

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A common treatment error is the use of antibiotics for common cold. Since common cold is a viral infection, antibiotics are ineffective. Worse still, they can cause side effects and bacteria may develop resistance with their indiscriminate use.

Common cold usually continues with its course irrespective of whether you take any medications or not. Currently, the best remedies for common cold are adequate rest with plenty of fluids.

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Reference:
1. http://www.cochrane.org/CD009345/ARI_antihistamines-common-cold
Source-Medindia