Supermarkets, grocery stores, and even gas stations offer a variety of over-the-counter (OTC) medications to help with a variety of ailments. Nyquil, Tylenol, and Benadryl are among the most common. However, there’s a lot to consider before picking these items off the shelf.

One of the most important considerations is whether the medication can make you drowsy. Drowsiness can severely impact your ability to drive, leading to wrecks and drug accident charges. Take a look at this list of common OTC medications that cause drowsiness to ensure you’re making the safe choice. 

What to Look For

When selecting an OTC drug, it’s vital that you look at the drug facts label for information. Underneath the “when using this product” section, the box or bottle should say if the medication might make you sleep or drowsy. 

Sometimes, the label might warn against operating a motor vehicle or machinery instead. However, there are still plenty of ingredients that can cause drowsiness whether this warning is present or not. These fall under common OTC categories including antihistamines, muscle relaxers, anti-emetics, and antidiarrheals. 


This category is primarily used to treat allergies, but can also be used for the common cold or the flu. Anything labeled for nighttime use is going to make you drowsy, which is why daytime versions of these medications exist. 

However, allergy medications with the drug diphenhydramine can take drowsiness to a new level by making it difficult to focus and slowing your reaction time. Several employees who have been wrongfully terminated took medications with diphenhydramine, like Benadryl, causing their employers to think they were under the influence. 

Muscle Relaxers

In most cases, OTC muscle relaxers are not powerful enough to make you drowsy. However, taking more than the recommended dose can cause this and other more serious symptoms. Always follow the dosage instructions on the bottle. 


These medicines treat dizziness, nausea, and vomiting. Most are used in relation to motion sickness, though there are a few other uses. Nearly all of these medications can cause drowsiness and impair your ability to operate a motor vehicle. Try them at home first to see how they impact you. 


As the name suggests, these medications are used to treat diarrhea. They slow down your intestinal contractions, buying you extra time in-between your bathroom breaks and allowing your body to absorb more water instead of flushing it out. 

Like anti-emetics, most also cause drowsiness and impact your ability to drive a vehicle. Both anti-emetics and antidiarrheals will warn users against driving or operating machinery. Out of all four categories, antihistamines with diphenhydramine are the most dangerous in terms of impacting your cognitive function.

Always check the label for warnings and impacts on the user before taking any OTC medication. You might also want to ask your primary care physician of these types of medications are alright for you to take, as they can have conflicting impacts with some prescribed medicines.