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Overview: Moxifloxacin is an antibiotic used to treat a variety of bacterial infections. The most common side effects are nausea, diarrhea, headache, and dizziness. Do not drive or do other activities that require alertness or coordination until you know how moxifloxacin affects you.  Stop this medicine and call your health care provider right away if you get a rash.

Uses

What is moxifloxacin used for?

Moxifloxacin is an antibiotic that is commonly used for the following infections caused by certain bacteria.

Moxifloxacin may not be appropriate for some of the infections listed above, depending on which germs are causing the infection. Bacteria in some locations may have developed resistance to moxifloxacin, which will make it not work as well.

Moxifloxacin may also be used for other conditions as determined by your health care provider.

Other forms of moxifloxacin are available for use in the eyes. See Moxifloxacin ophthalmic for more information.

How does moxifloxacin work (mechanism of action)?

Moxifloxacin kills certain types of bacteria by disrupting their ability to create and repair their DNA.

How is moxifloxacin supplied (dosage forms)?

Dosage forms and strengths

  • 400 mg oral tablets

Moxifloxacin is also available in injectable forms.

How should I store moxifloxacin?

Oral Tablets. Moxifloxacin tablets should be stored at room temperature, between 68 F and 77 F (20 C and 25 C). It can be exposed to temperatures between 59 F and 86 F (15 C and 30 C) for shorter periods of time, such as when transporting it. Store it in a cool, dry place.

Injection Liquid. Moxifloxacin injection is usually given by a health care provider in a hospital or clinic. You will not store it at home.

Side Effects

What are the most common side effects of moxifloxacin?

The most common side effects of moxifloxacin are listed below. Tell your health care provider if you have any of these side effects that bother you.

  • Nausea
  • Diarrhea
  • Headache
  • Dizziness

There may be other side effects of moxifloxacin that are not listed here. Contact your health care provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of moxifloxacin?

While less common, the most serious side effects of moxifloxacin are described below, along with what to do if they happen.

Tendon Problems. Moxifloxacin may increase your risk of tendon rupture or injury. Tendons are the connectors between your bones and muscles. Problems with tendons can happen in people who are taking moxifloxacin or who have taken it in the past several months. This can possibly lead to tendon swelling, also called tendonitis, or tearing of the tendon. It is most common with the tendon on the back of your ankle, called the Achilles tendon, but can also happen with other tendons. Stop using moxifloxacin, rest the affected area, and get medical help right away if you hear or feel a snap, see bruising right after an injury, or cannot move or put weight on a limb.

Nerve Problems. Nerves are the fibers that carry sensations from your body to the brain. Damage to these nerves, called peripheral neuropathy, can happen in people who are taking moxifloxacin. Stop taking moxifloxacin and call your health care provider if you develop pain, burning, tingling, numbness, or weakness in your arms, hands, legs, or feet.

Hallucinations or Psychotic-like Behaviors. Moxifloxacin may cause hallucinations or psychotic-like behaviors. It may also cause memory trouble, confusion, decreased awareness of your surroundings, trouble sleeping, or nightmares. Stop taking moxifloxacin and tell your health care provider right away if you have any of the following symptoms, or if you have been told by others you have these symptoms.

  • Hearing, seeing, smelling, tasting, or otherwise perceiving things that others do not
  • Delusional thoughts, such as false beliefs that you are being controlled
  • Disorganized thoughts, such as jumping between topics or having a hard time focusing
  • Sudden decline in self-care, such as personal hygiene or academic/work performance
  • Feeling unusually suspicious (paranoia), restless, agitated, anxious, or nervous
  • Aggressive behavior

Suicidal Thoughts or Actions. Moxifloxacin may increase the risk of suicidal thoughts or actions in a small number of people. If you are about to harm yourself, call 911 or call or text 988, the Suicide & Crisis Lifeline. Stop taking moxifloxacin and call your health care provider right away if you have any of the following symptoms.

  • New or increased thoughts of suicide or death
  • Suicide attempt
  • New or increased feelings of anxiety, depression, or other unusual changes in your mood or behavior

Seizures. Some people who have taken moxifloxacin have reported having seizures. There are many different types of seizures, and some of them are not easy to recognize. Stop taking moxifloxacin and call your health care provider if you have any of the following signs that a seizure is happening or could happen.

  • Muscle twitching, jerking, spasms, tremors, or other uncontrolled movements
  • Stiffening of your arms and legs
  • Feeling anxious, nervous, confused, or a sense of dread
  • Feeling dizzy or lightheaded
  • Falling or losing consciousness

Heart Rhythm Changes. Moxifloxacin may cause a rare, dangerous heart rhythm problem called QT prolongation and torsade de pointes. Some people have a higher risk of this, including people who are older, have other people in their family who have had these conditions, have low potassium or magnesium levels, or who take medicines that can prolong the QT interval. Tell your health care provider right away if you faint or have changes in your heart rate or rhythm, such as a fast or skipping heartbeat.

Severe Allergic Reactions. Moxifloxacin may cause allergic reactions, which can be serious. Stop taking moxifloxacin and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Liver Damage. Liver damage, also called hepatotoxicity, can happen when taking moxifloxacin. Call your health care provider right away if you have any of the following symptoms of liver damage.

  • Nausea or vomiting
  • Stomach or belly pain
  • Fever
  • Weakness or unusual tiredness
  • Itching
  • Loss of appetite
  • Light-colored poop
  • Dark-colored urine (pee)
  • Your skin or the whites of your eyes turning yellowish in color (also called jaundice)

Increased Pressure Around the Brain. Moxifloxacin can increase the pressure around the brain, a serious condition called pseudotumor cerebri (or increased intracranial pressure). Stop taking moxifloxacin and call your health care provider right away if you have any of the following symptoms.

  • Dizziness
  • Nausea and vomiting
  • Severe headache
  • Vision changes

Aortic Aneurysm and Dissection. Tell your health care provider if you have ever had swelling or a tear in the large artery that carries blood from the heart, called the aorta. Get emergency help if you have sudden symptoms related to this condition, such as chest pain, stomach pain, or back pain.

Antibiotic-associated Diarrhea. An overgrowth of germs called Clostridioides difficile, or “C. diff,” can happen in your gut with many types of antibiotics, including moxifloxacin. This can cause a condition known as antibiotic-associated diarrhea and can happen even up to two months after stopping the antibiotic. Call your health care provider right away if you have any of the following symptoms of this condition.

  • Watery diarrhea
  • Diarrhea that does not go away
  • Blood in your stool (poop)
  • Severe stomach cramps
  • Fever that starts after you start or finish the medicine

Joint Problems. Children under 18 years old can develop problems with their joints during and after treatment with moxifloxacin. Tell your child’s health care provider if they develop any joint problems.

High Blood Sugar (Hyperglycemia). Moxifloxacin may increase your blood sugar levels. Talk to your health care provider about how to maintain healthy blood sugar levels while you are taking this medicine.

Low Blood Sugar (Hypoglycemia). Moxifloxacin can cause low blood sugar, which can be serious and may lead to death. You may need to check your blood sugar more often if you have changes to your diet, exercise plan, or medicines for diabetes. Do not use moxifloxacin and call your health care provider right away if you have any of the following symptoms of hypoglycemia.

  • Headache
  • Crankiness or anxiety
  • Hunger
  • Dizziness or confusion
  • Blurry vision
  • Slurred speech
  • Sweating
  • Feeling jittery or shakiness
  • Fast heartbeat
  • Seizures

Sensitivity to Sunlight. Your skin may be very sensitive to light from the sun and devices that give off similar light, such as sunlamps and tanning beds, while you are taking certain drugs, including moxifloxacin. This is called photosensitivity. Use sunscreen and wear a hat and clothes that cover your skin if you need to be in the sunlight. Exposing your skin to this kind of light, even for a short time, can cause your skin to be severely sunburned, blistered, or swollen. Tell your health care provider right away if any of these happen.

Warnings & Precautions

Who should not use moxifloxacin?

Allergies to Ingredients. People who are allergic to any of the following should not take moxifloxacin.

  • Moxifloxacin
  • Avelox
  • Any other medicine known as a fluoroquinolone antibiotic or quinolone antibiotic
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific moxifloxacin products they stock.

What should I know about moxifloxacin before using it?

Do not take moxifloxacin unless it has been prescribed to you by a health care provider. Take it as prescribed.

Do not share moxifloxacin with other people, even if they have the same condition as you. It may harm them.

Keep moxifloxacin out of the reach of children.

Moxifloxacin can affect your alertness or coordination. Do not drive or do other activities that require alertness or coordination until you know how moxifloxacin affects you.

You should stay well-hydrated by drinking plenty of fluids while taking moxifloxacin. 

You should avoid taking moxifloxacin within four hours before or eight hours after taking antacids, multivitamins, or supplements that contain magnesium, aluminum, zinc, or iron. These may decrease the amount of moxifloxacin your body absorbs. Thus, moxifloxacin may not work well.

People who are under 18 or over 60 years old can be at greater risk of some side effects from moxifloxacin. Talk to your health care provider about your risks if you are in one of these age groups.

What should I tell my health care provider before using moxifloxacin?

Tell your health care provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them find out if moxifloxacin is right for you.

In particular, make sure that you discuss any of the following.

Heart Problems. Tell your health care provider if you or anyone in your family has a history of heart attack, a slow heartbeat (bradycardia), or an irregular heartbeat (arrhythmia), especially a condition called QT prolongation or long QT syndrome.

Other Current and Past Health Conditions. Tell your health care provider if you have any of the following.

Other Medicines and Supplements. Moxifloxacin may interact with other medicines and supplements. Before taking moxifloxacin, tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. See the Interactions section for more details.

Pregnancy. It is not known if or how moxifloxacin could affect pregnancy or harm an unborn baby. Tell your health care provider if you are pregnant or plan to become pregnant.

Breastfeeding. It is not known if moxifloxacin passes into breast milk. Tell your health care provider if you are breastfeeding or plan to breastfeed. Your health care provider will advise you if you should stop breastfeeding or stop moxifloxacin.

Interactions

Does moxifloxacin interact with foods or drinks?

There are no known interactions between moxifloxacin and foods or drinks.

There are no known interactions between moxifloxacin and alcohol, but heavy drinking can slow your immune response and make it harder for your body to fight infection.

Does moxifloxacin interact with other medicines (drug interactions)?

Always tell your health care provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following before taking moxifloxacin.

  • An antacid, supplement or laxative containing aluminum, magnesium, zinc, or iron
  • Sucralfate (Carafate), which is a medicine used to treat certain ulcers
  • A nonsteroidal anti-inflammatory drug (NSAID), such as ibuprofen, naproxen, and others, which is in many prescription and OTC products for pain, swelling, and fever
  • Warfarin, which is a blood thinner
  • A medicine for diabetes
  • A corticosteroid, which is a medicine for certain inflammatory conditions
  • An antipsychotic, which is a medicine for certain mental health conditions
  • A tricyclic antidepressant, such as amitriptyline, nortriptyline, or protriptyline, even if it is not used for depression
  • A diuretic, also called a water pill, which is a medicine used to reduce edema (fluid retention) and blood pressure
  • Erythromycin (Erythrocin), which is an antibiotic used for a variety of infections and other conditions
  • Medicines that can cause QT prolongation, such as amiodarone, procainamide, quinidine, or sotalol, which is a potentially dangerous heart rhythm problem

This may not be a complete list of medicines that can interact with moxifloxacin. Always check with your health care provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much moxifloxacin?

If you or someone else has used too much moxifloxacin, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of moxifloxacin?

It is important to complete your prescribed course of moxifloxacin, even if your symptoms get better or go away. This will reduce the risk that future infections are resistant to moxifloxacin or other similar medicines.

Oral Tablets. If you miss a dose, take it as soon as you remember. If less than eight hours remain before your next dose, skip the missed dose and only take the next dose at your regular time. Do not take double or extra doses.

Injection Liquid. Moxifloxacin injection is usually given by a health care provider in a hospital. Your health care provider will make sure you are receiving moxifloxacin as scheduled.