Monodox (Doxycycline): Uses, Side Effects, Dosage

By Zina Semenovskaya, MD
Medically reviewed checkmarkMedically reviewed
January 4, 2022

Doxycycline is a tetracycline antibiotic that treats a variety of bacterial infections throughout the body, including acne and skin, eye, and urinary tract infections.

In the United States, doxycycline is only available by prescription for adults and children who are at least 8 years old.

And it’s very commonly prescribed: In 2019, doxycycline was prescribed more than 21 million times for outpatient conditions.

One of the popular brands of doxycycline is called Monodox. 

In this article, I’ll discuss what infections Monodox can be used to treat, its side effects, and how to take it.

I’ll also break down what happens if you take too much and what to avoid while taking it.

What is Monodox?

Monodox is a brand of doxycycline that treats various bacterial infections by preventing the growth of bacteria.

The medication comes as capsules that contain varying amounts of doxycycline, and they’re taken by mouth. 

Monodox works by interfering with bacterial cells’ protein synthesis.

Without these proteins, the bacteria can’t function.

Monodox doesn’t necessarily kill the bacteria, but stops it from reproducing. 

Monodox cannot be used to treat viral infections like the cold or flu.

It can, however, treat a host of bacterial infections, from infections of the skin and eye to infections of the intestinal, genital, lymphatic, and urinary systems.

It can also treat certain infections that are spread by lice, mites, ticks, and infected animals.

And for people who are allergic to penicillin, doxycycline may be used for some cases of food poisoning.

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Monodox Uses


Monodox treats acne by killing the bacteria that infects pores, decreasing the oily substance that causes acne.

The medication can also be used to decrease the inflammation that causes rosacea and superficial abscesses. 

Urinary tract infections

Urinary tract infections (UTIs) happen when bacteria begins to multiply in the bladder after entering the urinary tract through the urethra.

While the body has natural defenses to prevent the bacteria from entering, they aren’t always successful.

When that occurs, the bacteria can cause an infection.

Antibiotics like Monodox are typically a second-line treatment for UTIs, depending on what kind of bacteria is in the urine. 

Intestinal infections 

Mondodox can be used to treat some severe cases of gastrointestinal infections caused by bacteria like E. coli.  

Respiratory infections 

Monodox can be used to treat bacterial respiratory tract infections, including pneumonia, a lung infection that causes symptoms resembling those of an upper respiratory tract infection (cough, fever, sore throat, etc.).

It may also be prescribed to treat acute bronchitis when it is caused by a bacterial infection. 

Eye infections

Monodox is a common oral prescription for certain types of eye infections.

Not only can it help kill the bacteria, but the medication is also a strong anti-inflammatory agent. 

Sexually transmitted infections (STIs)

Monodox is used to treat several common STIs caused by bacteria, including chlamydia.

Spread during oral, anal, or vaginal sex, chlamydia can affect the ureatha, throat, or rectum. 

Periodontitis (gum disease)

After a dental procedure, Monodox can be used to treat periodontitis, commonly known as gum disease.

If the gum disease isn’t advanced, Monodox can be used on its own.

For more serious cases, interventions by a dentist are also needed.

Monodox works to reduce bacteria and prevent them from filling periodontal pockets, the spaces or openings that surround the teeth beneath the gum line.

Bacteria that cause infection can easily fill these pockets and lead to tooth loss, so it’s important to treat them. 


Doxycycline can be prescribed to prevent malaria or taken in combination with another medication to treat the disease.

For adults, 100 mg capsules are the standard dosage for malaria.

They should be taken with fluid and food. 

Always follow your doctor’s or pharmacist instructions when taking doxycycline.

If you’re prescribed it to prevent malaria, start taking a dose per day one or two days before traveling to an area where malaria occurs.

While there, continue taking one dose per day and then for 28 days in a row after you leave.

While doxycycline can help prevent malaria, it doesn’t fully protect against it.

Take other protective measures like sleeping under mosquito nets, using insect repellent, wearing protective clothing, and staying in screened areas, particularly during the early evening through dawn.   

Monodox Side Effects 

Monodox may cause the following symptoms:

Call your doctor immediately if you experience these more serious side effects:

You should also seek medical attention if you experience watery or bloody stools, fever, or stomach cramps while taking doxycycline, or for up to two months after stopping treatment.

How to Take Monodox

Follow your doctor or pharmacist’s instructions as well as the patient directions that come with the medication. 

It’s best to take Monodox on an empty stomach, one hour before a meal or two hours after a meal.

If you find that it upsets your stomach, you may take it with a small amount of food.

Depending on your doctor’s instructions, take Monodox one or two times a day with a full glass of water.

Since the medication works best if you take it at regular intervals, try to take it at the same time (or times) each day. 

Even if your symptoms start going away early, keep taking the medication for the entire duration for which it is prescribed.

If you stop too soon, bacteria may keep growing and lead to the infection coming back.

It may also decrease the effectiveness of the treatment and increase the chances that the bacteria will develop a resistance to Mondox or other antibacterial drugs in the future.  

If your symptoms aren’t disappearing or they’re getting worse despite taking Monodox, inform your doctor. 

What happens if I miss a dose?

If you miss a dose, take the medicine immediately.

But don’t take two doses at once: If it’s almost time to take your next dose, skip the dose you missed.  

What happens if I take too much?

In the event of an overdose, call the Poison Control helpline at 1-800-222-1222.

Seek emergency medical attention immediately if you or someone taking Monodox has trouble breathing, has collapsed, had a seizure, or won’t wake up. 

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What to Avoid While Taking Monodox

Don’t take other antibiotics with Monodox unless your doctor advises otherwise.

Two hours before and after taking Monodox, avoid taking calcium supplements, antacids, multivitamins, iron supplements, or laxatives.

These products can prevent your body from absorbing doxycycline.

After taking the medication, don’t lie down for about an hour to prevent acid reflux.

You should also stay out of direct sunlight, as Monodox may cause your skin to be more sensitive to sunlight.

If you do go outside, wear sunscreen, sunglasses, and protective clothing.

How K Health Can Help

If you’re experiencing symptoms of a bacterial infection mentioned in this article, K Health can help determine if Monodox is right for you.

Did you know you can get affordable primary care with the K Health app? Download K Health to check your symptoms, explore conditions and treatments, and if needed text with a provider in minutes. K Health’s AI-powered app is based on 20 years of clinical data.

Frequently Asked Questions

What is Monodox used to treat?
Monodox is used to treat different kinds of bacterial infections, including eye infections, skin infections, respiratory infections, STIs, and more. It can also help prevent malaria and treat acne.
Is doxycycline a powerful antibiotic?
Yes, Mondox is a powerful antibiotic that prevents the growth of bacteria throughout the body. In fact, it’s so strong that you may start to feel better after only a few days of taking it. But even if you start to feel better, it’s important to finish the course of the medicine, as you risk developing a resistance to it in the future.
Can Monodox treat a UTI?
Yes, Monodox can be used to treat a UTI.
Does Monodox affect birth control?
Monodox may make hormonal contraceptives, including birth control pills, rings, patches, and injections less effective. Always tell your doctor if you are taking any medications or supplements when you are being prescribed antibiotics.
K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

Zina Semenovskaya, MD

Dr. Semenovskaya specializes in emergency medicine, and received her medical degree from Weill Cornell Medical College. She is currently the medical director at Remote Emergency Medicine Consulting, LLC and splits her time working clinically as an emergency medicine attending in California and Alaska. She is the first of our doctors to be fluent in Russian.

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