Amoxicillin Drug Interactions
The way amoxicillin works in the body can change if you take other medications or herbal products along with it. Taking drugs that are known to interact with amoxicillin increases your risk for developing serious side effects. It can also cause the medication not to work properly.
Some of the drugs that are known to interact with amoxicillin include:
- probenecid (Benemid)
- allopurinol (Aloprim, Zyloprim)
- warfarin (Coumadin)
- Yaz, Yasmin
Other antibacterial drugs
Each of this class of drugs reacts differently when taken with amoxicillin. Probenicid tends to decrease the excretion of amoxicillin in the kidney thereby increasing the risk for drug toxicity.
The blood thinning effects of oral anticoagulants particularly warfarin are potentiated by amoxicillin resulting in an abnormally prolonged prothrombin time. This puts the patient at an increased risk for bleeding. Therefore it is important to closely monitor patients taking amoxicillin along with anticoagulant drugs. Dose adjustments may be necessary to prevent abnormal bleeding tendencies.
Taking allopurinol and amoxicillin concurrently has been associated with increased risk for rashes. It is unclear whether the increased incidence of rashes is caused by allopurinol or the abnormally high uric acid levels of these patients.
Amoxicillin is known to reduce the effectiveness of birth control pills, patches or rings. It affects the re-absorption of estrogen thereby reducing efficacy of the contraceptive. Usually, your healthcare provider will recommend using a different birth control method along with estrogen-based contraceptive.
Meanwhile, taking other antibacterial drugs listed above may interfere with the pharmacokinetics or drug action of amoxicillin. Taking different antibiotics concurrently affects the metabolism of the drugs thereby resulting in reduced potency and efficacy of amoxicillin.
Since amoxicillin affects almost all types of bacteria, vaccination using vaccines that contain live bacteria is not recommended in patients taking this drug. Some healthcare providers recommend vaccination weeks after completing the antibiotic treatment.
Amoxicillin is also known to affect the result of some diagnostic tests, more specifically, urine glucose tests such as Benedict’s Solution, CLINITEST and Fehling’s Solution. This drug can cause a false-positive result in the urine glucose test. Because of the effect of amoxicillin in these laboratory tests, use of other reliable diagnostic procedures is recommended in patients taking amoxicillin.
How to prevent possible drug interactions?
First of all, you should inform your healthcare provider if you are taking any of the medications listed above. In fact, you are advised to tell your doctor of all the products (including prescription and nonprescription medications, herbal supplement and other health products) that you currently or regularly use. Avoid taking over-the-counter medications without consulting your healthcare provider.
Finally, although these drug interactions are possible, they do not always happen. Each person reacts differently with different kinds of drugs. Your healthcare provider is in the best position to evaluate what drugs you need to avoid while on amoxicillin.