Amoxicillin is a popular antibiotic used for many infections. While it’s a powerful and effective medication, a few claim to feel a little fatigued or drowsy after they take it. But does amoxicillin make you tired?

What Does Amoxicillin Do?

Amoxicillin is a penicillin antibiotic used to treat bacterial (not viral) infections, such as chest infections such as pneumonia and bronchitis, meningitis, sepsis, whooping cough, and dental abscesses. Most doctors usually prescribe it together with other antibiotics and medicines to treat stomach ulcers. For children, it’s also used to remedy ear infections

Amoxicillin is strictly available on prescription and in capsule or liquid form (if you’re not into capsules). It’s also given by injection but is usually only administered in hospitals.

This penicillin-based antibiotic fights infections in the body immediately within an hour upon ingesting it. The efficacy of this medication depends on the person’s consistent use of multiple doses per day. It normally relieves symptoms well within 72 hours, or sometimes even sooner, depending on their condition.

Most doctors also recommend taking amoxicillin for sexually-transmitted diseases like chlamydia, for which the Centers for Disease Control and Prevention (CDC) recommends taking 500 mg of amoxicillin orally three times per day for seven days. A study also found that religiously administering amoxicillin to gonorrhea patients resulted in a cure rate of up to 100%

Does Amoxicillin Make You Tired & Sleepy? – Side Effects

Does amoxicillin make you sleepy — or even tired? – Yes, it does, but it’s not a common occurrence. Antibiotics, in general, can sometimes cause someone to feel sleepy and tired. Aside from amoxicillin, azithromycin and ciprofloxacin have also been found to occasionally cause these symptoms. 

One plausible reason is the commonly-held belief that tiredness and sleepiness are signs of the antibiotics/medication at work combating the bacteria ravaging the body or that they could be affecting the neurotransmitters in the brain. Then again, these symptoms are rare, even for most patients dependent on amoxicillin. 

Another reason could be amoxicillin misuse, which could lead to liver injury/disease. While amoxicillin is a safe drug even when administered to patients with chronic liver disease or cirrhosis, studies show that the combination of amoxicillin with clavulanate and this combination is currently the most common cause of drug-induced liver disease in the United States and Europe. One known symptom of liver disease is chronic fatigue, which could explain this occurrence, though most scientists agree that instances of amoxicillin harming the liver are rare.

At any rate, If you think an antibiotic may be causing you to feel constantly sleepy or tired, talk to your doctor to see if they switch you to another antibiotic/medication that will not likely trigger these side effects.

Since many of the conditions that antibiotics are used to treat can also cause fatigue or sleepiness, ask your provider additional questions to help figure out whether or not your fatigue is a side effect of the condition itself or by the medication being taken.

Other Side Effects 

The more common side effects of amoxicillin oral tablet can include:

  • Headaches
  • Nausea
  • Vomiting
  • Appetite loss
  • Diarrhea
  • Rashes
  • Vaginal yeast infection
  • Abnormal sense of taste

Serious side effects include: 

  • Allergic reactions (e.g., hives, swelling of the face, lips, or tongue)
  • Breathing problems
  • Dizziness
  • Trouble sleeping
  • Seizures
  • Unusual bleeding or bruising

Another serious side effect of amoxicillin is hypersensitivity reactions. Symptoms can include:

Flu-like symptoms (e.g.fever, body aches, or sore throat), a painful red or purple rash that spreads throughout the body, and blisters that tend to break down and cause open sores.

These side effects may go away within a few days or a couple of weeks if they are mild. To combat symptoms like headaches or the feeling of being sick, stick to eating a balanced meal without any oily or spicy food. Drinking lots of water can also help if you’re experiencing diarrhea. 

Consult your doctor or pharmacist immediately if they’re more severe or don’t go away.


The following medications/drugs have been found to interact with amoxicillin, each with varying levels of interaction:

  • Allopurinol (Minor)
  • Amiloride (Minor)
  • Anisindione (Moderate)
  • Azithromycin (Minor)
  • Balsalazide (Moderate)
  • Bcg (Major)
  • Bifidobacterium infantis (Moderate)
  • Cholera vaccine, live (Major)
  • Clarithromycin (Minor)
  • Demeclocycline (Moderate)
  • Dicumarol (Moderate)
  • Dirithromycin (Minor)
  • Doxycycline (Moderate)
  • Entecavir (Moderate)
  • Erythromycin (Minor)
  • Estradiol (Moderate)
  • Ethinyl estradiol (Moderate)
  • Guar gum (Moderate)
  • Indium oxyquinoline in-111 (Moderate)
  • Lactobacillus acidophilus (Moderate)
  • Lactobacillus reuteri (Moderate)
  • Lactobacillus rhamnosus (Moderate)
  • Lactobacillus rhamnosus gg (Moderate)
  • Methotrexate (Major)
  • Minocycline (Moderate)
  • Mycophenolate mofetil (Moderate)
  • Mycophenolic acid (Moderate)
  • Oxytetracycline (Moderate)
  • Pemetrexed (Moderate)
  • Probenecid (Minor)
  • Sarecycline (Moderate)
  • Sodium iodide i-123 (Moderate)
  • Sodium iodide-i-131 (Moderate)
  • Tetracycline (Moderate)
  • Troleandomycin (Minor)
  • Typhoid vaccine, live (Major)
  • Warfarin (Moderate)

The Best Time To Take Amoxicillin

Amoxicillin is usually taken three times a day, so it’s recommended to space the doses evenly throughout the day, for example, in the morning, mid-afternoon, and before bedtime. You can take amoxicillin with a glass of water before or after having a meal.

In case you forget to take a dose on schedule, take it as soon as you remember unless it’s nearly time for your next dose. Never take 2 doses simultaneously or an extra dose to make up for the one you missed. Simply leave out the missed dose and take your next dose at the usual time.


Amoxicillin is a powerful antibiotic that effectively combats various bacterial infections. Side effects often happen occasionally, but these are usually mild and go away on their own or after doing simple remedies. Symptoms like fatigue or drowsiness are rare, but it’s still unclear whether it’s harmless or not. 

If the side effects don’t go away or become persistent, consult your doctor immediately to help you switch treatments.  

Disclaimer: this article does not constitute or replace medical advice. If you have an emergency or a serious medical question, please contact a medical professional or call 911 immediately. To see our full medical disclaimer, visit our Terms of Use page.

Written by