What are the most common adverse reactions when using amoxicillin?
Elijah King
Updated on March 12, 2026
What are the most common adverse reactions when using amoxicillin?
Common side effects of Amoxil include:
- nausea.
- vomiting.
- diarrhea.
- stomach pain.
- vaginal itching or discharge.
- headache.
- rash, and.
- swollen, black, or “hairy” tongue.
What should you not mix with amoxicillin?
Common medications that may interact with amoxicillin include:
- allopurinol (may increase the incidence of rash)
- anticoagulants (blood thinners), such as warfarin (may prolong bleeding time)
- oral contraceptives (may decrease absorption leading to reduced efficacy)
What are bad reactions to antibiotics?
The most common side effects of antibiotics affect the digestive system. These happen in around 1 in 10 people.
- vomiting.
- nausea (feeling like you may vomit)
- diarrhoea.
- bloating and indigestion.
- abdominal pain.
- loss of appetite.
Are side effects common with amoxicillin?
Most of the time, it is not caused by a serious medical problem. Stomach discomfort or nausea is a common side effect of amoxicillin. Less common symptoms include abdominal pain and vomiting. Taking your dose of amoxicillin with a meal may help prevent this side effect.
What are the signs of an allergic reaction to amoxicillin?
Symptoms
- Skin rash.
- Hives.
- Itching.
- Fever.
- Swelling.
- Shortness of breath.
- Wheezing.
- Runny nose.
What does an allergic reaction to amoxicillin look like?
It looks like flat, red patches on the skin. Smaller, paler patches usually accompany the red patches on the skin. This is described as a “maculopapular rash.” This type of rash often develops between 3 and 10 days after starting amoxicillin.
Can you take allergy medicine with amoxicillin?
No interactions were found between amoxicillin and Benadryl Allergy. This does not necessarily mean no interactions exist. Always consult your healthcare provider.
How long does amoxicillin side effects last?
Most side effects are temporary and will fade when treatment ends. Some amoxicillin side effects, however, are delayed and may take longer to resolve, such as allergic reactions and blood disorders. Clostridium difficile infection can be delayed for up to two months after amoxicillin treatment has stopped.
How long after taking amoxicillin would an allergic reaction occur?
The type of rash that develops depends on whether the person is experiencing an allergic reaction to amoxicillin or not. A maculopapular rash will usually appear around 3 to 10 days after a person first takes the medication, although it can occur at any time.
How long does it take for amoxicillin side effects to wear off?
After taking an oral dose of amoxicillin, 60% of it will be out of your system in 6 to 8 hours. The body excretes amoxicillin in the urine. It can take longer to get rid of amoxicillin in people with decreased kidney function, including the elderly. Side effects are more likely when this happens.
How long does it take to get over allergic reaction to amoxicillin?
The rash is not contagious and usually begins to fade after 3 days but may take up to 6 days to disappear. People taking amoxicillin may also develop hives. Hives appear as raised, red bumps that can come and go and change location and are usually very itchy.
How long does it take amoxicillin to get out of your system?