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How Effective Is Doxycycline for Strep?

Erik J.J. Goserud
Erik J.J. Goserud

Doxycycline, an antibiotic drug, can be an effective treatment for strep throat but is not usually the best or most recommended choice. A lot of this depends on the individual patient, particularly when it comes to his or her tolerance for medications that are generally considered to be better cures. Doxycycline for strep is usually most effective in children and people who have weak or compromised immune systems. Anyone with a tolerance for antibiotics or who has taken stronger drugs in this class before may not get very good results when it comes to throat ailments. This particular antibiotic is more commonly used in the treatment of acne and other chronic skin conditions.

Strep Throat Basics

Doxycycline is an antibiotic commonly prescribed for acne or STDs.
Doxycycline is an antibiotic commonly prescribed for acne or STDs.

Strep throat is a medical condition in which the throat and tonsils get infected with and inflamed by strains of Streptococcus bacteria — which is where the “strep” name comes from. This sort of inflammation often feels like an ordinary sore throat, though the causes and recommended treatment tend to be different.

Soreness caused by general dryness or irritation, as is often the case with the common cold, can normally be treated with throat lozenges or other over-the-counter cold and flu remedies. These won’t normally kill the Streptococcus bacteria, though. Antibiotics are usually required for this sort of job. Doxycycline is such a drug, but it is one of many. Depending on the circumstances, a different choice might be more effective.

How Doxycycline Works

Strep throat requires antibiotics for treatment.
Strep throat requires antibiotics for treatment.

Doxycycline is a member of the tetracycline family of antibiotics. It primarily targets low-grade bacterial infections and is most commonly prescribed to treat acne and skin conditions like rosacea, and may also be used to treat certain sexually transmitted diseases. In some cases it is also given to combat malaria, and can be an important part of Lyme disease treatment, too.

Throat lozenges can help relieve throat pain.
Throat lozenges can help relieve throat pain.

It typically works by launching a slow assault on bacterial strains in the body, wearing them down and systematically destroying them. People take the drug either in a capsule or as a liquid to be measured and swallowed. It must usually be taken at about the same time every day for a period of about a week. Antibiotics in the tetracycline family are often able to combat most sorts of bacteria, but they aren’t always the best choice for strep because of how advanced and quickly mutating the Streptococcus bacteria tends to be. People might start to feel better while taking this medication only for the strain to revive itself and come back stronger than ever.

Antibiotic Classes

A doctor can prescribe an effective alternative to doxycycline for those who have a tolerance to antibiotics.
A doctor can prescribe an effective alternative to doxycycline for those who have a tolerance to antibiotics.

Antibiotic drugs are classified into groups based both on ingredients and methodology. They all work in basically the same way, but different groups tend to be more effective when it comes to specific types of organisms and bacteria. Antibiotics in other families, particularly penicillin, may be more effective in the treatment of strep throat since these may be able to more effectively keep up with the Streptococcus mutations. The classes, uses, and effectiveness of antibiotics is constantly evolving, though, which makes getting a professional assessment essential to finding the right medication.

Side Effects

Amoxicillin and ciprofloxacin are the two most prescribed treatments for strep throat.
Amoxicillin and ciprofloxacin are the two most prescribed treatments for strep throat.

Doxycycline for strep can cause a number of side effects, but in most cases the worst thing is that it simply doesn’t cure the underlying condition. People might feel better, but the bacteria could just be dormant. This means that it can come back, usually stronger than it was before, after a few weeks or months. Other adverse reactions can include skin rash, itchiness, and nausea, particularly if the drug is taken on an empty stomach.

Importance of Completing the Course

Antibiotics are typically designed to work over a set period of time, and in most cases they kill bacteria according to a rather long-term plan. As a result, it’s usually very important for people to take the entire course of their prescription, even if they feel well or even healed before then. These sorts of drugs keep working even after a person’s initial symptoms have disappeared. Things can get worse and bacterial strains can actually get stronger if people take only part of their prescription.

What Bacteria Does Doxycycline Kill?

Doxycycline is known as a broad spectrum antibiotic, which means that it can target many different kinds of infections, including those caused by both gram positive and gram negative bacteria. This is important because gram negative bacteria feature a hardened cell wall that makes it more difficult to kill — but doxycycline has been proven effective even against them.

It has also been shown to kill anaerobic bacteria, which can be particularly harmful to humans. Anaerobic bacteria can kill tissue throughout the body by releasing toxins and producing destructive enzymes. Doxycycline kills anaerobic bacteria by thwarting its ability to synthesize protein, thus rendering it nonfunctional.

In addition to its effect on bacteria, doxycycline is also effective in treating parasitic infections such as Entamoeba and Balantidium coli infections. For this reason, it is commonly used as a prophylactic treatment for people planning to travel to places where these types of parasites may be more common.

Doxycycline Strep Dosage

Doxycycline is often used to treat infections caused by strep bacteria. The dosage for this treatment depends on several factors, including the location of the infection and the age of the patient. For adult strep infections affecting the throat, doctors will often prescribe a doxycycline treatment regimen of 100 mg per day. The treatment may include two doses in the first day and one dose for the remainder of the treatment period.

In some cases, the dosage may be divided into smaller, more frequent quantities. For example, some regimens call for 50 mg administered every six hours. For strep infections affecting children older than eight years old — but weighing under 45 kg — it may be calculated based on a patient’s body weight. In these cases, it is typically prescribed at 4.4 mg per day for every kilogram of weight.

The dosage of doxycycline may be reduced if it is paired with another antibiotic. Strep is sometimes treated by pairing doxycycline with amoxicillin, for example, which may necessitate a lower dose of both.

How Long Does It Take for Doxycycline to Work for Strep Throat

If you’re taking doxycycline as a treatment for strep throat, you’ve likely been prescribed antibiotics that last between seven and ten days. It will likely take the entire duration of your treatment to fully eradicate the strep infection. Stopping your treatment early can allow the bacteria to re-emerge and symptoms to return.

It’s likely that you’ll feel better within a few days of your doxycycline treatment, though. Many people report that symptoms of strep throat begin to fade within two to three days of starting a doxycycline treatment. Within five days, your symptoms may be entirely gone, but you should still complete the entire course of antibiotics that’s been prescribed by your healthcare provider.

Doxycycline usually eliminates a person’s contagiousness within 24 hours. This is important for anybody who’s taking time off school or work as they recover from a strep throat infection. Even if your symptoms persist, you should be able to return to regular activities without fear of spreading strep throat after a day of doxycycline treatment.

Frequently Asked Questions

What is doxycycline?

Doxycycline is an antibiotic used to treat bacterial infections. It is often used to treat infections brought on by the Streptococcus bacterium, generally known as “Strep,” and is a member of the tetracycline family of antibiotics. By preventing bacteria from growing, this medicine finally causes them to perish.

How effective is doxycycline in treating Strep?

When used as prescribed by a doctor, doxycycline has been shown in research to be quite efficient in treating strep. Doxycycline may be used to treat sinus infections, strep throat, and other bacterial diseases brought on by the Streptococcus bacterium, according to studies. Moreover, it has successfully treated illnesses brought on by susceptible bacteria, such as skin infections, urinary tract infections, and others.

Are there any side effects associated with taking doxycycline?

Taking doxycycline may have certain negative effects. Symptoms include diarrhea, nausea, and discomfort in the abdomen. Doxycycline may also induce photosensitivity, which can lead to sunburns if the drug is used without adequate sun protection.

How long does it take for doxycycline to start working?

Doxycycline often takes two to three days to start functioning. Nevertheless, this may vary according to the person and the degree of the illness. Generally speaking, in order to get the best outcomes from your prescription, you must take it exactly as your doctor instructs.

Is there anything I should avoid while taking doxycycline?

Certainly, there are some items you need to stay away from while taking doxycycline. They include consuming alcohol, using prescription drugs that could interact with doxycycline, and taking calcium supplements or antacids. In addition, you should avoid exposure to UV rays or direct sunlight since they might worsen skin sensitivities.

Discussion Comments


@sunshined-- Yes, that is something that is definitely not recommended for several reasons. I have been given doxycycline for strep before and started feeling so much better that I didn't take it for the entire time.

This was a mistake, as the strep came back and was even worse than it was the first time around. This time I made sure and took all of my medication even though I felt like I didn't need it. I didn't want to take the chance of having it come back for a third time.


When I had a bad acne flare up I was given some tetracycline to clear it up. I didn't end up using all of it and had some left over. A few months later I had a really bad sore throat and thought I would try this to clear it up. I know this isn't recommended, but since I didn't have any side effects when taking it before decided it was worth a try. The sore throat went away and never came back, so I am assuming it did the trick.


I know that doxycycline is effective for treating strep in many cases, but my body must have built up some kind of resistance to it. It is not uncommon for me to get strep at least twice during the cold and flu season.

After taking doxycycline at first, it quit working as well as it had in the past. I am so glad there are many other antibiotics they can use to take care of strep and other medical conditions that require antibiotics. I can't imagine what it would have been like before all these different antibiotics were available.


Whenever I start to get a sore throat I usually expect it to be strep. I have had this in the past, and know what it feels like. I have found the only way to get rid of this is to take antibiotics.

In the past I have tried to let it run its course, but this isn't something I would recommend. In my case, it never cleared up on its own, and I went spent too much time feeling miserable.

After I finally saw the doctor and started on some doxycycline, I began to feel better in a few days and my strep throat finally cleared up.

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    • Doxycycline is an antibiotic commonly prescribed for acne or STDs.
      By: Alexey Belikov
      Doxycycline is an antibiotic commonly prescribed for acne or STDs.
    • Strep throat requires antibiotics for treatment.
      By: Gorilla
      Strep throat requires antibiotics for treatment.
    • Throat lozenges can help relieve throat pain.
      By: kostrez
      Throat lozenges can help relieve throat pain.
    • A doctor can prescribe an effective alternative to doxycycline for those who have a tolerance to antibiotics.
      By: emiliau
      A doctor can prescribe an effective alternative to doxycycline for those who have a tolerance to antibiotics.
    • Amoxicillin and ciprofloxacin are the two most prescribed treatments for strep throat.
      By: Cheryl Casey
      Amoxicillin and ciprofloxacin are the two most prescribed treatments for strep throat.