You may not realize that common over-the-counter (OTC) drugs can cause serious side effects. These side effects can put your health at risk and interfere with your everyday activities.

Some of these side effects can be felt or sensed by you, but others can’t. Side effects you can usually feel are dizziness, drowsiness, double vision, headache, and vertigo. Those you may not feel include confusion, depression, or slow reactions. Any of these side effects can undermine or alter your perception, attention, and judgment. They can be especially dangerous if your job requires mental alertness and concentration.

Types of OTC medications that may cause these types of side effects are discussed later in this article.

Safety and productivity

The type of work you do and your workplace have an impact on any side effects. For example, an individual responsible for observing gauges in a control room may feel the drowsy effects of antihistamines more than someone employed in active physical work.

Environmental factors such as heat, humidity, cold, or exposure to chemicals may change the effects of certain medications. Someone working in a hot and humid environment will perspire a lot. This can lead to dehydration and an electrolyte imbalance. This imbalance can alter the way a drug works.

Consider your workplace

Experts say that patients and physicians need to be mindful of any workplace factors that could aggravate side effects of medications.

OTC antihistamines (allergy remedies), such as diphenhydramine, chlorpheniramine, brompheniramine, doxylamine, cetirizine, triprolidine, and loratadine, are good examples of how drugs can affect your activities. Many traditional antihistamines bring on side effects you can feel, such as drowsiness. They also bring on effects you can’t feel. These include impaired judgment, slowed reaction time, and slowed motor coordination and cognitive performance.

When activities that require mental alertness and concentration, such as work performance and driving, are performed while taking these drugs, the effect is troublesome and potentially hazardous.

Ask your doctor or pharmacist about alternative medications that are less sedating and don’t cause the same side effects.

OTC decongestants, stimulant laxatives, OTC sleep aids, heart burn remedies, and “stay awake or alert pills” can also cause side effects that interfere with daily activities.

What you can do

Read and heed the warnings on all medication packages and instructions . Don’t assume OTC medications are safe and won’t cause dangerous side effects.

Ask your pharmacist to check if the OTC medication interacts with any other medications you are taking. Antihistamines and cold and allergy medications may interact with other medications you are taking.

Always follow package directions when taking medications.

Avoid alcohol when taking medications. Alcohol can worsen the negative effects of many medications and can make you very drowsy when combined with antihistamines.