Written by Stacia Woodcock, PharmD | Reviewed by Christina Aungst, PharmD
Updated on April 22, 2024
Key takeaways:
If you’re feeling tired, it’s possible your medication is to blame. Common culprits include antihistamines, muscle relaxers, and benzodiazepines. Opioid pain medications commonly cause drowsiness, too.
Acetaminophen (Tylenol) and antibiotics aren’t known to make you drowsy. But they both treat conditions (pain, fever, and infection) that can make you feel more tired than usual.
In some cases, your energy will return as your body adjusts to the medication you’re taking. But let your healthcare team know if it doesn’t, or if your fatigue worsens. They can make adjustments to help get you feeling better.
Table of contents
Antihistamines
Muscle relaxers
Some antidepressants
Anti-seizure meds
Beta blockers
Opioids
Benzodiazepines
Antibiotics and fatigue
How long fatigue lasts
Bottom line
References
Maria Korneeva/iStock via Getty Images Plus
When you’re feeling tired, it can be hard to go about your daily activities. And this isn’t an uncommon problem. In fact, up to 45% of people in the U.S. experience fatigue.
Health conditions such as insomnia, depression, and stress can all contribute to fatigue. But is it possible that your medication is to blame? Can common medications, such as acetaminophen (Tylenol) and antibiotics, make you tired? Let’s review seven types of medication that can cause fatigue.
Antihistamines
Antihistamines are medications taken for allergies, hives, and itchy rashes. Some are also used to prevent nausea or help you sleep. So it should be no surprise that some antihistamines can make you feel drowsy if you take them during the day.
Older first-generation antihistamines are more likely to make you tired. These include over-the-counter (OTC) and prescription medications, including:
Diphenhydramine (Benadryl, ZzzQuil)
Chlorpheniramine (ChlorTabs)
Doxylamine (Unisom SleepTabs)
Hydroxyzine (Vistaril)
The newer second- and third-generation antihistamines are less likely to cause drowsiness. So if you’re looking for a non-drowsy option, you can give fexofenadine (Allegra) or loratadine (Claritin) a try. Cetirizine (Zyrtec), however, can cause drowsiness for some people.
Muscle relaxers
Muscle relaxants, commonly referred to as muscle relaxers, can help treat painful muscle spasms. But they can also make you feel drowsy. Commonly prescribed muscle relaxants include cyclobenzaprine, carisoprodol (Soma), and tizanidine (Zanaflex).
You should use caution when driving or doing other activities that require you to be alert when taking muscle relaxers. It’s also a good idea to avoid alcohol, since it can make your drowsiness worse.
Some muscle relaxers, such as metaxalone (Skelaxin), are less sedating than those listed above. So if drowsiness is bothersome, talk to your prescriber about a different treatment option.
Some antidepressants
Antidepressant medications are used to treat depression and anxiety. But they’re also prescribed for other health conditions, such as chronic pain, migraines, or insomnia. Fatigue is possible with most antidepressants, but some are more likely to make you feel tired than others, including:
Trazodone
Mirtazapine (Remeron)
Tricyclic antidepressants (TCAs), such as amitriptyline and doxepin (Silenor)
Monoamine oxidase inhibitors (MAOIs), such as selegiline (Emsam) and isocarboxazid (Marplan)
Selective serotonin reuptake inhibitors (SSRIs) include escitalopram (Lexapro), paroxetine (Paxil), and fluoxetine (Prozac). They can cause sleep problems that lead to daytime fatigue. But some SSRIs can make you feel drowsy without sleep problems, too. Overall, SSRIs are less likely to cause drowsiness than the antidepressants listed above. But they may be more likely to cause drowsiness than other options.
Serotonin and norepinephrine reuptake inhibitors (SNRIs) are similar to SSRIs in terms of making you feel tired. They include duloxetine (Cymbalta) and venlafaxine (Effexor XR).
Keep in mind that the side effects of antidepressants can vary from person to person. And often, the condition you’re treating could also be contributing to your fatigue. It typically takes 4 to 8 weeks for most antidepressants to start working and improve condition-related fatigue. Regular exercise and a balanced diet can help keep your energy levels up in the meantime.
Your prescriber may also be able to adjust your dose or when you take your antidepressant to help with daytime drowsiness. Or they may switch you to a medication that’s less likely to make you tired, such as bupropion (Wellbutrin SR, Wellbutrin XL).
Anti-seizure medications, such as topiramate
Antiepileptic medications treat seizures and certain mental-health conditions. They often cause drowsiness and dizziness. In fact, topiramate (Topamax) is an anti-seizure medication that’s often referred to as “Dopamax” because of this side effect. Other common examples include:
Lamotrigine (Lamictal)
Gabapentin (Neurontin)
Phenytoin (Dilantin)
Carbamazepine (Tegretol)
In most cases, drowsiness and fatigue caused by anti-seizure medications will go away over time. Your prescriber may slowly raise your dose when you first start taking one of these medications to minimize this side effect. But let them know if drowsiness doesn’t improve or is bothersome. They may need to adjust your medication to address it.
Beta blockers
Beta blockers can help treat a variety of conditions. They’re commonly prescribed for certain heart conditions, such as high blood pressure and irregular heart rate. They can also be used to prevent migraines and control tremors. Some examples of beta blockers are:
Metoprolol (Toprol XL, Lopressor)
Carvedilol (Coreg)
Bisoprolol
Propranolol
Beta blockers can make you feel tired. And you may feel more easily exhausted with daily activities, such as walking up a flight of stairs. Fatigue caused by beta blockers often improves over time as your body adjusts to the medication. But if it doesn’t, let your prescriber know.
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Good to know: Fatigue is a common side effect of many other medications that treat high blood pressure. Examples include calcium channel blockers, angiotensin-converting enzyme (ACE) inhibitors, and diuretics (water pills). If you’re feeling dizzy or faint along with fatigue, your blood pressure could be too low. It’s best to contact your healthcare team in this case, as your medication likely needs an adjustment.
Opioids
Opioid medications, such as hydrocodone / acetaminophen (Norco), oxycodone (Roxicodone, Oxycontin), and acetaminophen / codeine (Tylenol #3), are used to treat pain. And they’re highly sedating medications. Even tramadol (Qdolo, ConZip), a lower-strength opioid, can still cause significant drowsiness.
Be sure to use caution when driving while taking opioids. If the drowsiness they cause is bothersome, talk to your healthcare team. They may suggest a different pain medication for you.
Does Tylenol make you sleepy?
Opioids are often combined with acetaminophen (Tylenol). So it’s common to wonder if it’s acetaminophen that’s contributing to drowsiness. But acetaminophen isn’t associated with making you sleepy on its own.
But what about OTC sleep aids such as Tylenol PM (acetaminophen / diphenhydramine)? Well, these products contain acetaminophen and an antihistamine. Although acetaminophen can improve your sleep by reducing pain, it’s the antihistamine that makes you feel sleepy after you take it.
Benzodiazepines
Benzodiazepines (BZDs) are used to treat anxiety and seizure disorders. They’re also often prescribed for insomnia — so it makes sense that they can make you sleepy. Some examples include:
Lorazepam (Ativan)
Diazepam (Valium)
Alprazolam (Xanax)
Clonazepam (Klonopin)
If you take BZDs every day, it’s likely your body will adjust and you won’t feel as sleepy over time. But if you’re only taking them once in a while, it’s more likely you’ll feel drowsy after you take them. Talk to your prescriber if you’re feeling too sleepy while taking BZDs. They may change your dose or try a different medication.
Do antibiotics make you tired?
No, antibiotics don’t make you drowsy.
If you’re taking an antibiotic, such as amoxicillin (Amoxil) or erythromycin (E.E.S., Ery-Tab), you may feel tired. But it’s probably the infection itself — not the antibiotic — that’s causing your drowsiness. It’s your body’s way of telling you to slow down and rest so it can fight off what’s making you sick.
Also, some bacteria release toxins as they die, which can make you feel more tired once you start taking antibiotics to kill them off. Doxycycline (Doryx, Vibramycin) and ciprofloxacin (Cipro) are examples of antibiotics used to treat toxin-releasing bacteria.
Is drug-induced fatigue temporary?
Sometimes. In many cases, drowsiness will decrease or go away over time as your body adjusts to your medication. But that’s not always the case. Some medications may make you sleepy no matter what. Once you stop taking the medication, your energy will usually come back — but you shouldn’t stop taking any medication on your own. Several medications that cause fatigue can also cause withdrawal symptoms if they’re stopped abruptly.
If you think a medication you’re taking is making you too sleepy, talk to your healthcare team. They can help make sure there isn’t something else causing your symptoms. They can also make changes to your medication to help reduce it.
The bottom line
If you’re feeling drowsy, your medication may be the cause. Several medications, like diphenhydramine (Benadryl, ZzzQuil) and amitriptyline, may cause drowsiness. Often, this side effect will go away over time as your body adjusts to the medication — but this isn’t always the case.
Acetaminophen (Tylenol) and antibiotics aren’t known to cause drowsiness. But the conditions they treat (pain, fever, and infection) could make you more tired than usual. Contact your prescriber if you’re feeling too sleepy from your medication. They can help decide on the best course of action.
References
Bush, L. M. (2022). Overview of gram-negative bacteria. Merck Manual Consumer Version.
Cojocariu, S. A., et al. (2021). Neuropsychiatric consequences of lipophilic beta-blockers. Medicina.
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