Can you take doxycycline and amoxicillin together?

In this article:

• Why can’t you take doxycycline and amoxicillin together?
• Is doxycycline or amoxicillin better?
• Doxycycline vs. amoxicillin: Comparison chart

In this article

• Why can’t you take doxycycline and amoxicillin together?
• Is doxycycline or amoxicillin better?
• Doxycycline vs. amoxicillin: Comparison chart

Doxycycline and amoxicillin are two commonly prescribed and used antibiotics in medicine. However, they belong to different drug classes and are often used for different types of bacterial infections.

Doxycycline is a tetracycline antibiotic that works by stopping bacterial growth. It’s typically prescribed for skin conditions like rosacea and acne because it also reduces inflammation. On the other hand, Amoxicillin is a penicillin antibiotic that kills bacteria, which is why it is often prescribed to people needing antibiotics for common illnesses like pneumonia, bronchitis, sinusitis, urinary tract infections (UTIs), and the stomach infection H. pylori.

Although it may seem unusual to take more than one antibiotic at a time, this strategy can be helpful if the right drug combinations are carefully chosen and given together. According to Raj Singh, MD, primary care physician at HEALOR and medical director at RAREV Medical Spa in Las Vegas, using multiple antibiotics at once may increase the effectiveness of your treatment, helping you get better faster. It can also reduce the likelihood of bacteria-resistant infections. 

But what about taking doxycycline and amoxicillin together—is this a good combination? While technically safe, it’s usually not the best pairing, and healthcare providers generally avoid combining these two antibiotics. Here’s what to know. 

Why can’t you take doxycycline and amoxicillin together?

“Taking doxycycline and amoxicillin at the same time isn’t unsafe, but it’s not a preferred combination,” Dr. Singh says. Lab studies have shown that tetracycline antibiotics (like doxycycline) can reduce the effectiveness of other antibiotics, particularly penicillin-type antibiotics (like amoxicillin). In other words, taking doxycycline and amoxicillin together could make it harder for the amoxicillin to work as effectively as it should. 

Does that mean these two antibiotics can never be prescribed at the same time? “Not necessarily,” says Dr. Singh. “If someone is on doxycycline for a month for a bad skin infection or acne, for example, and they get an ear infection, you could prescribe a short course of amoxicillin. It’s not unsafe; we just don’t know if the amoxicillin will be as effective as it could be.”

However, you should make sure you communicate with your healthcare providers about all of the prescription drugs, including over-the-counter (OTC) medicines, vitamins, minerals, and herbs you’re taking, especially if you need to be prescribed more than one antibiotic at the same time. This is especially important if you have multiple healthcare providers who may not be aware of what the others have prescribed.

 “You could be prescribed one of these antibiotics by a specialist, like a dermatologist, and another by a primary care doctor,” says Joanna Lewis, Pharm.D., founder of The Pharmacist’s Guide. “It’s always important to let all providers know all of the medications you are taking so they can educate, monitor, and change therapy as needed.”

“There is also the possibility that being prescribed both of these antibiotics at once could increase the potential for some of the more common gastrointestinal side effects such as nausea, vomiting, diarrhea, and stomach pain,” Dr. Lewis says.

Is doxycycline or amoxicillin better?

There are several differences between doxycycline and amoxicillin. These drugs are often prescribed to treat different bacterial infections, so one isn’t necessarily better than the other. The choice between them may depend on the type of infection your healthcare provider is treating. 

Drug class 

Doxycycline is a tetracycline antibiotic, and amoxicillin is a penicillin-type antibiotic. According to Dr. Singh, this means they work differently. “Doxycycline is what we call a bacteriostatic antibiotic, which means it prevents the growth of bacteria, [while] amoxicillin is considered a bactericidal, which means it kills bacteria.”

Uses

Because these antibiotics treat infections differently, they’re used for different conditions. Dr. Singh says doxycycline can be used for malaria and tick bites but is generally used mostly for skin conditions like acne. On the other hand, he says amoxicillin is used more for ear, nose, and throat infections, including bronchitis and strep throat.

Side effects

Both amoxicillin and doxycycline can cause mild gastrointestinal side effects, such as nausea, diarrhea, and vomiting. Both carry a risk for severe allergic reactions or anaphylaxis. 

Doxycycline is generally well-tolerated compared to other drugs in its class and has limited evidence for causing serious adverse effects. However, it can cause additional mild side effects such as headaches, light sensitivity, itching or skin rashes, and, in rare cases, tooth discoloration.

Pregnancy and breastfeeding risks

Pregnant and breastfeeding women should always consult with their healthcare provider about the safety of any OTC and prescription medications, natural supplements, and herbals. But generally, only one of these antibiotics is safe to use during pregnancy—amoxicillin. “Doxycycline is generally not recommended during pregnancy because it can impact the tooth and bone development of fetuses,” Dr. Lewis says. 

For breastfeeding, amoxicillin is typically considered safe, but you should use caution when taking doxycycline. “If the therapy is short-term, it may be allowed by your provider, but some prefer to avoid doxycycline during breastfeeding as well,” Dr. Lewis says.  

Other drug interactions

Amoxicillin generally has few drug interactions. Dr. Singh says amoxicillin is, overall, a highly safe antibiotic with few side effects and drug-drug interactions. The only interaction he flags is with allopurinol, which is often prescribed to treat gout. “Taking these two medications together increases the chance of having an allergic skin reaction, like a rash,” Dr. Singh says. 

RELATED: Amoxicillin interactions to avoid

Doxycycline, on the other hand, interacts with more medications, which Dr. Singh says include:

• Certain seizure medications: Barbiturates and drugs like carbamazepine can reduce the effectiveness of doxycycline because they activate enzymes that break down antibiotics quickly. 
• Blood thinners: Taking doxycycline with drugs like warfarin can increase the risk of bleeding and may also make warfarin last longer in your bloodstream, possibly increasing its toxicity.
• Pepto Bismol: This common OTC medication for upset stomach can reduce the absorption of doxycycline in the gut.

As always, remember that your healthcare provider is the best person to decide on the right course of antibiotic treatment for you. Although it’s not usually a preferred combination, there may be situations when it may be necessary to take doxycycline and amoxicillin together. Always consult your healthcare provider if you have any questions about taking antibiotics that are prescribed to you.