Amoxicillin Interactions

Amoxicillin can reduce the elimination of methotrexate from your body, which can increase your risk of developing side effects. If you are taking these medications together your doctor may want to increase your normal methotrexate monitoring (testing your blood, liver and kidneys). You should also report any side effects such as a sore throat to your doctor.

Certain blood thinners (anticoagulants), including warfarin, may interact with amoxicillin. This may increase your risk of bleeding, therefore it is important to let whoever monitors your blood thinner testing (INR) know you are taking it.

Allopurinol, a medication to treat gout, can interact with amoxicillin, causing an increased risk of developing a skin rash. You should speak to your doctor if this occurs.

Amoxicillin can reduce the effectiveness of the oral typhoid vaccine. It therefore should not be taken within three days (before or after) of the vaccine. Let your doctor know if you are taking amoxicillin and are due to have this vaccine.

If you suffer from vomiting and diarrhoea as a side effect of amoxicillin, be sure that you discuss it with your doctor. If you are unable to take your other regular medication, some issues may arise. One example would be the contraceptive pill, which can put you at risk of pregnancy if you are unable to take it or keep it down. There are many other important medications that can’t be missed and it is something to think carefully about or discuss with your doctor.

There are several medications to avoid, but here are some of the main ones.

Medications to be cautious about

1. Antacids

   • Antacids containing aluminium or magnesium hydroxide (e.g., Gaviscon, Rennie) may reduce the absorption of amoxicillin, potentially lowering its effectiveness.

2. NSAIDs (e.g., ibuprofen):

   • It is generally safe, but excessive use could increase the risk of kidney strain, especially if you are already dehydrated or have kidney concerns. Consult a healthcare provider if unsure.

3. Laxatives:

   • Some laxatives, especially those with magnesium (e.g., milk of magnesia), may also reduce amoxicillin absorption.

Amoxicillin is unlikely to interact with any other over-the-counter medicines, however you should speak with your pharmacist first before deciding to start taking any new over-the-counter medicines alongside amoxicillin.

There are some herbal medicines that can interact with amoxicillin such as acacia, chewing catha and bromelain. There's a limited number of studies on the safety of taking herbal medicines alongside prescribed medications, so generally it is best to avoid doing so.

Can I take amoxicillin with painkillers?

Yes, amoxicillin is generally safe to take with common painkillers like paracetamol and ibuprofen. However, you should avoid combining it with aspirin or other nonsteroidal anti-inflammatory drugs (NSAIDs) without medical advice if you have a sensitive stomach, as this combination might increase the risk of stomach irritation.

Does amoxicillin interact with alcohol?

There’s no direct interaction between amoxicillin and alcohol, meaning alcohol won’t reduce the effectiveness of the antibiotic. However, drinking alcohol can worsen potential side effects like nausea, dizziness, and stomach upset. It’s best to limit alcohol intake while recovering from an infection to avoid additional strain on your body.

Can I take amoxicillin with oral contraceptives?

Amoxicillin may reduce the effectiveness of some oral contraceptives under rare circumstances by affecting gut bacteria that help with hormone absorption. Although the risk is low, using a backup method of contraception, such as condoms, is recommended during and for seven days after finishing the antibiotic course.

What happens if I take amoxicillin with blood thinners?

Amoxicillin may increase the effects of blood-thinning medications like warfarin, potentially raising the risk of bleeding. If you are on blood thinners, your doctor may monitor your INR (a measure of blood clotting) more closely during treatment.

Does amoxicillin affect probiotics or gut health?

Amoxicillin can disrupt gut bacteria, potentially leading to side effects like diarrhoea. Probiotics may help restore healthy gut flora, but they should be taken a few hours apart from amoxicillin to ensure the antibiotic doesn’t reduce their effectiveness.

Can I take amoxicillin with antihistamines?

Yes, amoxicillin can generally be taken with antihistamines like loratadine or cetirizine. However, always check with a pharmacist if you’re using combination medications that contain other active ingredients.