What can you do if your medication makes you drowsy?

You expect to feel tired if you take sleeping pills. But when other medications make you sleepy, it can interfere with your daily life.

“Many medicines can have this side effect,” said Barb Hergert, PharmD, a clinical pharmacist in Optum’s Clinical Engagement Services Center.

Antihistamines are among the most common medications that can cause drowsiness. This includes over-the-counter (OTC) brands like Benadryl (diphenhydramine) and Zyrtec (cetirizine).

Some other medications that may cause sleepiness include:

• antianxiety medications
• antidepressants
• antipsychotic medications
• antiseizure medications
• beta-blockers
• muscle relaxers
• opioids

Knowing more about the drugs that can cause drowsiness can help you take steps to manage this side effect.

Why do some medications make you drowsy?

The reason some medications make you sleepy depends on the type of medication. For example, drugs that slow your heart rate, such as benzodiazepines, can have a relaxing or sedative effect on your body, which can lead to drowsiness.

According to Hergert, everyone reacts to medicines differently, so it’s hard to generalize. For example, beta-blockers lower your heart rate, which could leave you feeling a little tired.

Antihistamines like Benadryl (diphenhydramine) and Zyrtec (cetirizine) work differently. These medications work by blocking histamine, a chemical that your body makes. It’s responsible for an allergic reaction causing congestion, sneezing, and itchy eyes.

But histamines also work on your brain. They block receptors that regulate sleep and wakefulness. So when you take an antihistamine to get relief from your allergies, it may also affect your sleep cycle.

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What can you do if a medication is causing drowsiness?

Hergert said, “If you’re just starting on a medication that’s known to cause drowsiness, avoid doing activities that require alertness — such as driving — until you know how it affects you. Then give it a few weeks. Your body may adjust to the medication, and you’ll start to feel less drowsy.”

If a few weeks go by and you’re still feeling drowsy, Hergert suggests that you reach out to your doctor. They may be able to recommend ways to reduce or eliminate the drowsiness. For instance, it may be that the dose or the time of day you take the medication should be adjusted.

In some cases, your doctor may recommend a different medication. Just be sure you make this decision with your doctor’s help. You shouldn’t make these kinds of changes on your own.

Are there ways to stop an antihistamine from making you sleepy?

Antihistamines can be first-generation or second-generation. First-generation antihistamines are more likely to cross the blood–brain barrier. This means they directly affect the brain and the central nervous system, making drowsiness more likely.

Hergert explained, “Older, first-generation antihistamines are more likely to cause drowsiness. These include diphenhydramine (Benadryl), chlorpheniramine (Chlor-Trimeton), and hydroxyzine (Vistaril).

If you take one of these medications, consider taking it at bedtime. Alternatively, you can talk to your doctor about switching. Newer, second-generation antihistamines are less likely to cause drowsiness. These include fexofenadine (Allegra), loratadine (Claritin), and cetirizine (Zyrtec).”

How do beta-blockers cause drowsiness?

Fatigue is a common side effect of beta-blockers like labetalol (Trandate) and acebutelol (Sectral). This is likely due to its effect on your heart rate and how it affects the release of hormones in your body.

Hergert added, “In addition to slowing your heart rate, beta-blockers also relieve pressure on the heart by blocking the action of certain hormones, such as adrenaline. And when you have less adrenaline, you may have less energy.

Most people can tolerate beta-blockers. But a small percentage may experience some drowsiness and fatigue.”

Should you stop taking a beta-blocker if it’s causing drowsiness?

Hergert emphasized, “No. Don’t stop on your own. Tell your doctor if you’re feeling fatigued and it’s not improving. Your doctor may suggest trying some strategies for addressing the problem without ignoring the health of your heart. Again, they may lower the dose or switch you to a different medicine.”

Stopping beta-blockers suddenly can lead to a condition called the beta-blocker rebound phenomenon. Symptoms include:

• fast heart rate
• chest pain
• headaches
• sweating
• high blood pressure

Speak with a doctor before stopping your medication. They will likely taper you off the drug and switch you to a different type of blood pressure medication.

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Could your antidepressant be causing drowsiness?

Hergert explained, “Generally speaking, antidepressants are known to cause sleep problems, including drowsiness. These medicines work by acting on certain neurotransmitters in the brain called serotonin and norepinephrine. These both elevate mood. But at the same time, these medicines can make you feel drowsy.

If your doctor prescribes an antidepressant, ask about the best time of day to take it. For instance, mirtazapine (Remeron) and trazodone (Desyrel) are often taken at bedtime. This is because they are known to cause drowsiness.

Other kinds of antidepressants, such as selective serotonin reuptake inhibitors, are not as likely to cause drowsiness. So you may be advised to take those during the daytime.”

Don’t suddenly stop taking your antidepressant. If it’s causing you to feel tired or drowsy, let your doctor know. They’ll likely reduce your dosage slowly to lower the risk of withdrawal symptoms.

What else can you do to reduce drowsiness?

Practicing certain healthy sleep habits may help improve the quality of your sleep. This includes:

• creating a relaxing bedtime routine
• sticking to a consistent sleep schedule
• avoiding electronic gadgets too close to bedtime
• keeping your bedroom dark, quiet, and cool
• avoiding large meals too close to bedtime

Also, try to avoid drinking caffeine close to your bedtime. Caffeine has a half-life of up to 6 hours, which means half of it will still be in your system 6 hours after consumption. Knowing this can help you decide when to drink your coffee.

Hergert also recommends eating a healthy diet and exercising regularly — but not too close to bedtime.

“A 30-minute walk is a good way to boost your energy. If you can’t get outside, try walking around your house 2 or 3 times a day for 10 or 15 minutes each time. That can really help.

And avoid alcohol while taking medication. It could make you even drowsier.”

Summary

Drowsiness is a known side effect of many different types of medications, including beta-blockers, antidepressants and even OTC antihistamines.

If your medication is causing you to feel overly drowsy, there are steps you can take. You can wait to see if this side effect goes away with time. Or, if an OTC medication is causing sleepiness, you could try taking it closer to bedtime.

If your drowsiness persists, talk with your doctor to see if they can change your dosage and the timing of your doses or switch you to a different medication.