We all get tired sometimes. But if you’re constantly dragging through the day—no matter how much sleep you get or how healthy you try to eat—your energy drain might be coming from somewhere unexpected: your medicine cabinet.

Common Pills

Believe it or not, some of the most commonly used pills can cause low energy, fatigue, and even mental fog as a side effect. And it’s not just the heavy-duty prescriptions—many over-the-counter (OTC) meds are culprits, too.

Here are 8 everyday pills that could be secretly draining your energy—plus what you can do about it.

1. Antihistamines (Allergy Medications)

Medications like diphenhydramine (Benadryl) or cetirizine (Zyrtec) can block histamines, which helps with allergies—but they also block other chemicals that help keep you alert. Even “non-drowsy” options can have this effect in some people.

2. Blood Pressure Medications

Beta-blockers like metoprolol or atenolol are lifesavers for your heart, but they can slow your heart rate so much that you feel sluggish or sleepy.

3. Antidepressants (SSRIs)

While they help with mood regulation, SSRIs like fluoxetine (Prozac) or sertraline (Zoloft) can cause fatigue—especially when first starting out or increasing the dose.

4. Antipsychotics or Mood Stabilizers

Used for conditions like bipolar disorder or schizophrenia, drugs like quetiapine (Seroquel) or lithium can have a major sedative effect—even when taken in small doses.

5. Sleep Aids (Prescription or OTC)

Ironically, sleep aids like zolpidem (Ambien) or melatonin supplements may leave you feeling groggy the next morning, especially if taken too late at night or if you don’t get a full 7–8 hours of rest.

6. Muscle Relaxants

Often prescribed after an injury, muscle relaxants like cyclobenzaprine (Flexeril) can cause serious drowsiness—even into the next day.

7. Pain Relievers with Codeine

Prescription pain meds that contain codeine or other opioids don’t just kill pain—they can also slow everything down, including your energy levels and alertness.

8. Heartburn Medications

Proton pump inhibitors (PPIs) like omeprazole (Prilosec) and H2 blockers like ranitidine (Zantac) may interfere with nutrient absorption (especially B12), which can lead to long-term fatigue.

What Should You Do?

One of These Pills Might Be to Blame… If you're on any of these medications and feel persistently drained, don’t stop taking them on your own. Instead, talk to your doctor. Sometimes a simple dosage change or switching to a different med can make a huge difference in how you feel.