Can Amoxicillin Make You Tired?

Antibiotics are medications that treat bacterial infections like urinary tract infections (UTIs), skin infections, strep throat, and more. As with any medication, many potential side effects can occur with antibiotic use. Some of the most common side effects include nausea, vomiting, diarrhea, bloating, and headache. Rarely, when you take antibiotics like amoxicillin (Amoxil), you also feel tired and weak. But is this due to the medication, the infection itself, or some other reason?

Keep reading to learn how amoxicillin affects your body and ways to manage fatigue.

Amoxicillin and Tiredness

Fatigue, drowsiness, or feeling tired is not a common side effect of antibiotics. However, it has been reported that some antibiotics, including amoxicillin, may cause you to feel tired or weak.

Other antibiotics that may have this side effect include:

• Cephalexin, a cephalosporin antibiotic
• Azithromycin, a macrolide antibiotic (reported by less than 1% in trials)
• Ciprofloxacin, a fluoroquinolone antibiotic
• Intravenous vancomycin

You can discuss the potential for fatigue with your healthcare provider and read the patient information to see if unusual weakness or tiredness is listed before starting the antibiotic.

Why Amoxicillin May Make You Tired

Amoxicillin is a penicillin antibiotic used to treat bacterial infections of the respiratory tract, skin, urinary tract, and ear, nose, and throat.

Feeling more tired than usual may be your body’s reaction to the infection. When bacteria are destroyed, they can release toxins that leave you weak. Your immune system is also expending energy to fight the infection, which can cause fever, malaise, and swelling. Getting extra rest is important while your body recovers.

Other factors that can contribute to fatigue include insomnia, depression, and stress, which may be worsened by illness.

Other Medications That Can Cause Fatigue

Common FDA‑approved medications that may cause tiredness include:

• Antihistamines such as diphenhydramine (Benadryl) and hydroxyzine
• Antidepressants and anti‑anxiety medications
• Muscle relaxers like cyclobenzaprine (Flexeril)
• Certain blood pressure medications, including metoprolol and verapamil
• Seizure and migraine medications
• Opioid pain medications like oxycodone and hydrocodone

How to Manage Fatigue While Taking Amoxicillin

It is important to complete the full course of antibiotics prescribed. Stopping early can cause the infection to return and promote antibiotic resistance.

If you feel unusually tired while on amoxicillin, try these tips:

• Eat healthy, balanced meals with fruits, vegetables, whole grains, and lean proteins
• Get plenty of rest and aim for high‑quality sleep by minimizing disturbances and screen time
• Stay hydrated to prevent dehydration‑related fatigue
• Avoid other substances that cause drowsiness, such as alcohol and certain antihistamines
• Take probiotics to help restore gut bacteria balance
• Exercise gently as tolerated to boost energy levels

If fatigue persists, consult your healthcare provider for further advice.

Other Side Effects of Amoxicillin

Common side effects include diarrhea, nausea, vomiting, abdominal pain, headache, taste changes, and yeast infections.

Rare but serious side effects include severe allergic reactions (hives, difficulty breathing, swelling of face or throat) and Clostridioides difficile‑related diarrhea (frequent, foul‑smelling stools, fever, stomach cramps). Seek immediate medical attention if these occur.

Takeaway

If you are ill, you may feel weak and fatigued regardless of medication. You should start to feel better within a few days of starting amoxicillin. If symptoms worsen or do not improve, contact your healthcare provider to determine if a different treatment is needed.

Sources

• Mohsen S, Dickinson JA, Somayaji R. Update on the adverse effects of antimicrobial therapies in community practice. Can Fam Physician. 2020;66(9):651-659. Accessed July 10, 2025.
• Hansen MP, Scott AM, McCullough A, et al. Adverse events in people taking macrolide antibiotics versus placebo. Cochrane Database Syst Rev. 2019;1(1):CD011825. doi:10.1002/14651858.CD011825.pub2. Accessed July 10, 2025.
• Antibiotics. MedlinePlus. Accessed July 10, 2025.
• Amoxil – Amoxicillin tablet, film-coated. DailyMed. Accessed July 10, 2025.
• Azithromycin monohydrate label. DailyMed. Accessed July 10, 2025.