Amoxicillin with clavulanic acid (Augmentin) is a combination antibiotic often prescribed for pneumonia and ear, skin and urinary tract infections. Amoxicillin is in the same antibiotic drug family as penicillin. Clavulanic acid helps prevent bacteria from inactivating amoxicillin. Like any medication, amoxicillin with clavulanic acid can cause side effects. The most common side effects involve the digestive system and skin. Less commonly, this antibiotic can cause liver inflammation.
Digestive System Upset
Digestive system symptoms are the most common side effects of amoxicillin with clavulanic acid. Diarrhea occurs in approximately 10 percent of people taking this antibiotic, according to a January 2015 "Canadian Medical Association Journal" review article. Diarrhea caused by amoxicillin with clavulanic acid is typically mild and temporary. It usually occurs due to faster passage of food through the small intestine and an imbalance between different types of bacteria in the large intestine. In some cases, however, more severe diarrhea develops due to overgrowth of bacteria called Clostridium difficile in the colon. Nausea and vomiting are less common than diarrhea. Taking the medication at the start of a meal can help prevent stomach upset.
Approximately 5 percent to 10 percent of people who take amoxicillin and clavulanic acid develop a drug rash, according to an October 2010 report in the "Annals of Allergy, Asthma & Immunology." These rashes are usually mild and appear as flat pink patches with bumps. The typically itchy rash usually starts on the chest and back before spreading to the neck, arms and legs. The rash usually begins 1 to 3 days after starting the antibiotic but can be delayed for 1 to 2 weeks.
The January 2015 "Canadian Medical Association Journal" notes that amoxicillin with clavulanic acid increases the risk for yeast infections. The antibiotic kills normal bacteria in the mouth and on the skin while yeast continue to grow. This overgrowth of yeast can lead to genital and/or oral yeast infections. Symptoms of a genital yeast infection include itching and burning. Women may notice a thick vaginal discharge. Oral yeast infection symptoms include sores, white patches in the mouth and on the tongue and difficulty swallowing.
Liver inflammation is a rare but potentially serious side effect of amoxicillin with clavulanic acid. It occurs in approximately 10 people out of every 100,000 prescriptions, according to a July 2011 article in the "Journal of Antimicrobial Chemotherapy." Though symptoms can develop as early as a few days after starting amoxicillin with clavulanic acid, they usually appear after stopping the medication. Possible symptoms include fever, fatigue, abdominal pain and jaundice -- yellowing of the skin or whites of the eyes. People who already have liver disease, are older than 65, drink heavily or take amoxicillin with clavulanic acid for a prolonged period are more likely to develop liver inflammation.
Severe Skin Reaction
Amoxicillin with clavulanic acid can cause rare but serious skin reactions called Stevens-Johnson syndrome and toxic epidermal necrolysis. A generalized feeling of being sick along with fever, headache, cough and eye irritation develops 1 to 3 weeks after starting the antibiotic. A red rash follows that progresses to blisters and loss of the superficial layer of skin within a few days, much like a severe burn. This type of skin reaction is potentially life-threatening.
Warnings and Precautions
Amoxicillin with clavulanic acid can cause anaphylaxis, a rare but severe allergic reaction that can be life-threatening. Seek emergency medical care if you develop difficulty breathing, itching, hives, dizziness, flushing or swelling of your lips, tongue or face. Emergency care is also needed if you develop symptoms of a serious skin reaction.
As of July 2015, amoxicillin with clavulanic acid is classified by the U.S. Food and Drug Administration as a pregnancy category B drug. This means there is no evidence of an increased risk of birth defects based on animal studies. Amoxicillin with clavulanic acid is considered relatively safe during pregnancy and while breastfeeding, but discuss the potential risks and benefits with your doctor.