Amoxicillin Drug Interactions: Medicines, Foods and Supplements to Avoid

Amoxicillin is one of the most prescribed antibiotics in the world, and for most people it plays well with almost everything. That reputation is mostly deserved, but “mostly” matters. A small number of medicines, a couple of vaccines, and a few habits can change how amoxicillin behaves, or how the other medicine behaves, and some of those combinations deserve a call to your pharmacist before the first dose.

Instead of dumping a giant list on you, this guide sorts amoxicillin interactions into a three-light system: red (talk to your prescriber before combining), amber (usually manageable with monitoring or timing), and green (commonly worried about, but generally fine). You will also find a section on foods, drinks, and supplements, a quick reference table, and a pre-appointment checklist you can screenshot.

First, what “interaction” actually means

An interaction happens when one substance changes the way another one is absorbed, used by the body, or cleared out of it. With amoxicillin, there are four practical flavors:

• Clearance interactions: amoxicillin or the other drug blocks the kidneys from removing something, so levels rise.
• Effect interactions: a blood test or clinical effect shifts, such as a change in clotting numbers.
• Side-effect interactions: combining two drugs raises the chance of a particular reaction, such as a rash.
• Gut flora interactions: because antibiotics reshape intestinal bacteria, they can interfere with anything that depends on those bacteria, including some oral vaccines and, in theory, hormone recycling.

Amoxicillin is a penicillin-class antibiotic. Most of its meaningful interactions come from how it is removed by the kidneys, a pathway it shares with several other medicines.

Red light: talk to your prescriber before combining

1. Methotrexate

Methotrexate is used for certain cancers, rheumatoid arthritis, psoriasis, and other conditions. Penicillins, amoxicillin included, can compete with methotrexate for the kidney’s removal system, which can slow methotrexate clearance and let its level climb. Higher levels mean a higher chance of toxicity, with warning signs that include mouth sores, unusual bruising or bleeding, fever, and profound fatigue.

This does not always mean you cannot be treated with amoxicillin. It means your prescriber may check blood counts and kidney or liver tests more closely, or choose a different antibiotic. If you take methotrexate, make sure whoever prescribes amoxicillin knows, including urgent care and dental offices.

2. Probenecid

Probenecid is a gout medicine that also reduces the kidney’s removal of certain drugs. It blocks the tubular secretion of amoxicillin, so amoxicillin stays in the blood longer and at higher levels. In the labeling for amoxicillin-clavulanate, combining the two is described as not recommended. Occasionally clinicians pair them on purpose to boost antibiotic levels for specific infections, which is why this combination should only happen under a prescriber’s direction.

3. Live oral typhoid vaccine

The oral typhoid vaccine (Vivotif) contains live, weakened bacteria. Antibiotics can kill those bacteria before they trigger immunity, making the vaccine less effective. Travel clinics usually advise waiting a set period after finishing antibiotics before taking this vaccine. If you are planning international travel and are on a course of amoxicillin, mention it when you book your travel visit. Injectable vaccines are not affected in the same way.

4. A history of penicillin allergy

This is not a drug interaction, but it belongs in the red zone. Amoxicillin is itself a penicillin, so someone with a confirmed penicillin allergy should not take it unless an allergist has cleared them. Many people carry an allergy label that was never confirmed, which is a topic for our companion guide on amoxicillin rash vs allergy.

Amber light: usually manageable with monitoring or timing

5. Warfarin and other vitamin K antagonist blood thinners

Product labeling notes that abnormal prolongation of prothrombin time, reflected as a higher INR, has been reported in people taking amoxicillin together with oral anticoagulants. The effect is not seen in everyone, and it is often modest in a short course, but it matters because warfarin is a narrow-margin drug. If you take warfarin:

• Tell the prescriber before you start amoxicillin so an INR check can be planned.
• Watch for unusual bruising, nosebleeds, blood in urine or stool, or prolonged bleeding from small cuts.
• Do not change your warfarin dose on your own.

Newer blood thinners work differently and have fewer documented amoxicillin interactions, but your pharmacist should still review your list.

6. Allopurinol

Allopurinol lowers uric acid in gout. According to the labeling for amoxicillin-containing products, people taking both medicines develop skin rashes more often than people taking amoxicillin alone. It is not clear whether the cause is allopurinol itself or the high uric acid levels in the people who take it. A rash during this combination does not automatically mean a true penicillin allergy, but it should be reported promptly so the cause can be sorted out.

7. Hormonal birth control

This one has generated more anxiety than almost any other, so a careful answer is useful. Some drug labels state that antibiotics may disturb the intestinal flora and lower estrogen reabsorption, leading to reduced effectiveness of combined oral contraceptives. However, the evidence for amoxicillin is limited and debated. Large reviews have not shown a consistent drop in contraceptive effectiveness with most non-rifamycin antibiotics, and public health agencies generally do not require extra protection for typical antibiotic courses.

The practical approach many clinicians take:

• Take your pill exactly as scheduled.
• If vomiting or severe diarrhea occurs from the infection or the antibiotic, treat it like missed pills, because the pill may not be absorbed.
• If pregnancy would be a serious concern, consider a backup method such as condoms during the course and for the week afterward, and ask your clinician or pharmacist what they recommend.

Rifampin and rifabutin are the antibiotics with a well-established contraceptive interaction; amoxicillin is not in that category.

8. Mycophenolate

Mycophenolate is an immunosuppressant used after transplants and for some autoimmune conditions. Reports suggest that certain antibiotics, including amoxicillin combined with clavulanate, can lower levels of mycophenolate’s active form in the blood. Transplant teams are well aware of this and may monitor more closely. If you take it, never start an antibiotic without letting the transplant or rheumatology team know.

9. Tetracycline-type antibiotics (doxycycline, minocycline, tetracycline)

The classic teaching is that bacteriostatic antibiotics, which slow bacterial growth, may blunt the effect of bactericidal penicillins, which work by killing growing bacteria. In practice, the clinical importance varies by infection, and combinations are sometimes used deliberately. The simple takeaway: do not combine antibiotics without a clinician’s say-so. If you have leftover doxycycline from a previous illness, do not take it alongside amoxicillin.

10. Other drugs cleared by the kidneys

Because amoxicillin leaves the body mainly through the kidneys, people with reduced kidney function may need a dose adjustment, and combinations with other drugs that stress the kidneys deserve extra attention. Typical examples include high-dose NSAIDs and certain diuretics in people who are dehydrated. For most healthy adults this is not an issue, but it explains why clinicians ask about your kidney health.

Green light: common worries that are usually fine

11. Over-the-counter pain relievers

Acetaminophen and ibuprofen do not have a significant direct interaction with amoxicillin for most people. If you are on warfarin, adding an NSAID raises bleeding risk on its own, so check first. If you have a sensitive stomach, taking an NSAID with food helps. For information on how pain medicines interact in other combinations, our guides to gabapentin and ibuprofen and Percocet and ibuprofen show the kind of questions to ask.

12. Antihistamines and cold medicines

Common allergy and cold products do not typically change amoxicillin levels. They can, however, mask an early hive reaction. If you take an antihistamine and a new rash still appears, that is worth noting. Our explainers on Claritin for hives and Claritin with Flonase cover non-drowsy options.

13. Most antidepressants, ADHD medicines, and heart or blood pressure drugs

Amoxicillin has no documented major interaction with the large classes of SSRIs, stimulants, or common blood pressure medicines. If you take any of these, your own medicine’s guide may have more to say about its other interactions. We maintain deep dives on Prozac drug interactions, Luvox drug interactions, and Adderall drug interactions for that purpose.

Quick reference table

Foods and drinks: what you really need to avoid

Here is the pleasant surprise: amoxicillin has very few food restrictions. Immediate-release capsules, tablets, and liquid can be taken with or without food, because studies comparing fed and fasting states have not found a meaningful difference in how much drug is absorbed. Many clinicians still suggest taking it with a meal or snack because it reduces nausea and stomach upset.

Dairy, calcium, and iron

Unlike tetracyclines and fluoroquinolones, amoxicillin does not bind tightly to calcium or iron, so yogurt, milk, cheese, and calcium-fortified foods are fine. You do not need to schedule your doses around them.

Extended-release amoxicillin

One exception to the “with or without food” rule applies to extended-release amoxicillin products, which are recommended to be taken with a meal. If your prescription is an extended-release form, follow the label.

Alcohol

There is no dangerous chemical reaction between amoxicillin and alcohol, unlike the severe reaction seen with metronidazole. But that does not make alcohol a good companion. It can worsen nausea, dizziness, and stomach upset, contribute to dehydration, and make it harder for your body to recover from the infection you are treating. Many clinicians suggest skipping alcohol until the course is complete and you feel better. If you do drink, keep it light and drink water. The same logic applies to other medicines, which you can see in our articles on Claritin and alcohol and sildenafil and alcohol.

Grapefruit and citrus juice

Grapefruit interferes with certain liver enzymes that process many other medicines. Amoxicillin is not among the drugs known to be affected, so grapefruit is not on the avoid list for this antibiotic. The evidence that acidic juice or soda blunts amoxicillin is thin.

Probiotics and fermented foods

Antibiotics can disrupt your gut bacteria, and diarrhea is one of the most common side effects. Probiotic foods and supplements are generally considered safe alongside amoxicillin and may help reduce antibiotic-associated diarrhea in some people. A common recommendation is to separate a probiotic supplement from the antibiotic dose by a couple of hours so the antibiotic does not act on the live organisms immediately. If you are immunocompromised, have a central line, or are seriously ill, ask your clinician before taking probiotics.

Supplements and herbal products

Supplements are less thoroughly studied than prescription drugs, so the honest answer in this category is often “limited data.” Here is a sensible way to handle it.

• Vitamin C, vitamin D, zinc, and a standard multivitamin: no well-documented interaction with amoxicillin. Spacing multivitamins that contain minerals a couple of hours from your dose costs nothing and is a cautious habit.
• Guar gum and some fiber supplements: small studies suggest certain gums can reduce the absorption of oral amoxicillin. Space fiber products away from your dose and ask your pharmacist about your specific product.
• Bromelain: an enzyme from pineapple that has been reported in small studies to increase amoxicillin levels in the blood. It is not a reason to panic, but it is a reason to mention it.
• St. John’s wort and other herbs affecting liver enzymes: amoxicillin is not mainly broken down by those enzymes, so major effects are not expected, though the herb can interact with many other medicines you may be taking.
• Activated charcoal: can bind drugs in the gut. Do not take it around the same time as your antibiotic.
• Herbal “immune boosters” and “antibiotic alternatives”: these are not replacements and should never be used to skip or shorten a prescribed course.

Lab tests and screening results amoxicillin can affect

Interactions are not limited to other medicines. A few lab-related effects are worth knowing about, particularly if you have diabetes or are scheduled for testing soon:

• Urine glucose tests: very high concentrations of amoxicillin in urine can cause false-positive results with certain older chemical urine sugar tests that rely on copper reduction. Enzyme-based glucose tests are not affected in the same way. If you test urine sugar at home, ask which method your kit uses.
• INR monitoring: as noted above, people on warfarin may see changes, so a scheduled check matters.
• Stool and gut-related tests: a recent antibiotic course can change the bacterial makeup of stool samples. Tell the lab or your clinician if you have taken antibiotics before a microbiome or infection test.
• Infection cultures: starting an antibiotic before a sample is taken can make a culture look negative. If your clinician wants a swab or sample, give it before the first dose when possible.

Tell any clinician who orders a test that you are taking or recently took an antibiotic. It takes five seconds and can prevent a misread result.

What about amoxicillin with clavulanate (Augmentin)?

The combination product shares the amoxicillin interactions above and adds a few points to be aware of. Clavulanate is associated with a higher rate of diarrhea and, rarely, liver injury, so people with existing liver disease or prior reactions to the combination need individualized advice. Probenecid raises amoxicillin levels but not clavulanate levels, which is part of why the combination with probenecid is not recommended. Taking it at the start of a meal is generally advised to improve tolerance and absorption of the clavulanate component.

Special situations

Kidney disease

Doses are often lowered or spaced further apart when kidney function is reduced. If you have chronic kidney disease, make sure the prescriber has a recent estimate of your kidney function.

Pregnancy and breastfeeding

Amoxicillin is among the antibiotics commonly used in pregnancy and compatible with breastfeeding, though the decision belongs to your own clinician. Small amounts reach breast milk and can occasionally cause loose stools or thrush in an infant.

Infectious mononucleosis

Not an interaction between drugs, but between a drug and a virus: amoxicillin given during mononucleosis is well known to trigger a widespread rash in a large share of cases. If you have a sore throat that turns out to be mono, antibiotics are not helpful and can cause that rash.

Children

Dosing for children is based on weight and the exact liquid concentration, so never use an adult dose or a kitchen spoon. The label and your pediatric clinician’s instructions determine the amount.

A pre-appointment checklist to save or screenshot

1. List every prescription, including inhalers, patches, injections, and eye drops.
2. List every over-the-counter medicine, vitamin, herb, and supplement you take, even occasionally.
3. Note any history of penicillin or cephalosporin reactions, including what happened and when.
4. Mention kidney, liver, or bleeding conditions.
5. Say whether you use hormonal contraception, and whether pregnancy or travel vaccines are on the horizon.
6. Tell the prescriber about alcohol use, since it affects how you will feel on any antibiotic.
7. Ask: “Is there anything I should avoid while on this, and is there any test I need?”

Warning signs while taking amoxicillin

Mild nausea, loose stools, and a slightly upset stomach are common. Contact your clinician promptly if you notice:

• Severe or bloody diarrhea, particularly if it starts during or weeks after antibiotics, which can signal C. difficile infection
• Yellowing of the skin or eyes, dark urine, or severe abdominal pain
• Unusual bleeding or bruising
• A new rash, especially one with hives, blisters, or peeling skin (see our rash vs allergy guide)
• Swelling of the face, lips, or tongue, wheezing, or trouble breathing, which requires emergency care

Frequently asked questions

Can I take amoxicillin with ibuprofen or Tylenol?

For most people, yes. Neither has a notable direct interaction. Check first if you take warfarin, have kidney disease, or have a history of stomach ulcers.

Does amoxicillin make birth control fail?

Evidence is mixed, and some product labels mention a possible reduction. Many experts consider the risk low, but if avoiding pregnancy is critical, a backup method during the course is a reasonable precaution. Vomiting or severe diarrhea is a more reliable cause of failure.

Can I drink alcohol on amoxicillin?

There is no dangerous reaction, but alcohol can worsen side effects and slow recovery, so skipping it is the better choice.

Should I take amoxicillin on an empty stomach?

You can, but taking it with food often reduces nausea. Extended-release forms should be taken with a meal.

Can I take probiotics with amoxicillin?

Generally yes, spaced a couple of hours apart. Ask first if you are immunocompromised.

What if I take warfarin?

Tell the prescriber before the first dose so your INR can be monitored, and report any bleeding or bruising.

Is it safe to take with other antibiotics?

Only if a clinician has prescribed the combination on purpose. Never combine leftover antibiotics.

How long after finishing amoxicillin can I get a typhoid vaccine?

Ask your travel clinic. The timing depends on the vaccine type, and the oral live vaccine is the one affected.

Key takeaways

• The red-light list is short: methotrexate, probenecid, the live oral typhoid vaccine, and any penicillin allergy history.
• Warfarin, allopurinol, hormonal contraception, and mycophenolate fall into the monitor-or-plan category.
• Food, dairy, and grapefruit are not major issues, but alcohol is best avoided.
• Probiotics are usually fine, spaced from the dose.
• Bring a full medicine and supplement list to every antibiotic prescription.

For official drug information, the National Library of Medicine’s MedlinePlus amoxicillin page is a reliable plain-language reference, and you can look up current prescribing labels on DailyMed.

Medical disclaimer: This article is for general education only and is not medical advice. Interactions depend on dose, health conditions, and other factors. Always check with a pharmacist or prescriber before combining amoxicillin with another medicine or supplement, and never stop a prescribed antibiotic course early without clinical guidance.