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Overview: Norfloxacin is an antibiotic used to treat certain infections caused by bacteria. Common side effects include dizziness, nausea, diarrhea, and headache. Do not drive or do other activities that require alertness or coordination until you know how norfloxacin affects you. Stop taking this medicine and call your health care provider right away if you get a rash.

Uses

What is norfloxacin used for?

Norfloxacin is commonly taken by certain people for the following infections.

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

Norfloxacin only treats certain infections caused by bacteria. It will not work for infections caused by viruses, such as the common cold, the flu, or coronavirus. It also will not work for any other infections that are not caused by bacteria. Taking norfloxacin or any other antibiotic when it is not needed may cause the antibiotic to not work for bacterial infections in the future.

Note: FDA-approved forms of norfloxacin have been discontinued and are no longer available in the United States.

How does norfloxacin work (mechanism of action)?

Norfloxacin kills certain types of bacteria by stopping them from making and repairing their DNA.

How is norfloxacin supplied (dosage forms)?

Brands and other names

  • Noroxin

Dosage forms and strengths

  • 400 mg oral tablets

How should I store norfloxacin?

Norfloxacin 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 in a tightly closed container, in a cool, dry place.

Side Effects

What are the most common side effects of norfloxacin?

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

  • Dizziness
  • Nausea
  • Diarrhea (see below)
  • Heartburn
  • Headache
  • Stomach cramps
  • Feeling unusually weak or tired
  • Change in liver function tests

There may be other side effects of norfloxacin 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 (800-332-1088). 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 norfloxacin?

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

Severe Allergic Reactions. Norfloxacin may cause allergic reactions, which can be serious. Stop taking norfloxacin 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 or skin rash
  • Bumps on the skin called hives, which can be red, pink, white, or brown depending on your skin tone
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Tendon Problems. Tendons are the connectors between your bones and muscles. Problems with tendons can happen in people who are taking norfloxacin 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 (ruptured 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. Your risk may be higher if you are older than 60, taking certain medicines, or had a kidney, heart, or lung transplant. Strenuous exercise may also increase the risk. Stop taking norfloxacin and get medical help right away if you have any tendon pain, bruising, or swelling, hear or feel a snap in a tendon area, or are unable to move or bear weight on a joint.

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 norfloxacin. Sometimes nerve problems do not go away even after you stop taking norfloxacin. Stop taking norfloxacin and call your health care provider right away if you have pain, burning, tingling, numbness, weakness, or increased sensitivity in your arms, hands, legs, or feet.

Hallucinations or Psychotic-Like Behaviors. Norfloxacin may cause hallucinations or psychotic-like behaviors. Stop taking norfloxacin and tell your health care provider right away if you have any of the following symptoms or 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, confused, or nervous
  • Aggressive behavior
  • Trouble sleeping or nightmares

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

  • Dizziness
  • Nausea and vomiting
  • Severe headache or a headache that does not go away
  • Vision changes, including blurred vision

Seizures. Some people who have taken norfloxacin have reported having seizures. There are many different types of seizures, and some of them are not easy to recognize. Stop taking norfloxacin 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

Antibiotic-Associated Diarrhea. An overgrowth of germs called Clostridioides difficile, or C. diff, can happen in your gut with many types of antibiotics, including norfloxacin. This can cause a condition known as antibiotic-associated diarrhea and can happen even two months or longer 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

Heart Rhythm Changes. Norfloxacin 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 take medicines that can prolong the QT interval. Stop taking norfloxacin and 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.

Suicidal Thoughts and Actions. Norfloxacin may cause 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 norfloxacin 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 mood or behavior

Liver Damage. Liver damage, also called hepatotoxicity, can happen when taking norfloxacin. 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 (also called jaundice)

Severe Skin Reactions. Norfloxacin can cause severe skin reactions, such as Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN), that can lead to death if not treated. If you get a rash, stop taking norfloxacin and call your health care provider right away. Get emergency help if you have any of the following symptoms of SJS or TEN.

  • Painful red or purple skin that looks burned and peels off
  • Flat red rash or blisters on your skin, mouth, nose, and genitals
  • Red, painful, watery eyes
  • Flu-like symptoms, including fever, chills, and muscle aches

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 norfloxacin. This is called photosensitivity. Limit or avoid sunlight, and use sunscreen and wear a hat and clothes that cover your skin if you need to be in the sun. Exposure 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 norfloxacin?

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

  • Norfloxacin
  • Noroxin
  • Any other medicine known as a fluoroquinolone
  • Any of the ingredients in the specific product dispensed

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

Tendon Problems. You should not take norfloxacin if you have ever had a tendon problem, including tendonitis or a tear in one of your tendons, from this medicine or a similar antibiotic (fluoroquinolone).

What should I know about norfloxacin before using it?

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

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

Keep norfloxacin out of the reach of children.

You should stay well hydrated by drinking plenty of fluids while taking norfloxacin. Take norfloxacin with a glass of water.

Norfloxacin may cause dizziness and lightheadedness and can affect your alertness or coordination. Do not drive or do other activities that require alertness or coordination until you know how norfloxacin affects you.

People who are younger than 18 or older than 60 can be at greater risk of some side effects from norfloxacin. Talk to your health care provider about your risks if you are in these age groups.

You should not take norfloxacin with or within two hours before or after taking an antacid, multivitamin, or supplement that contains aluminum, calcium, iron, magnesium, or zinc. These products may decrease how well your body absorbs norfloxacin and make the medicine not work as well.

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

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 know if norfloxacin 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 had 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 or have had any of the following.

Other Medicines and Supplements. Norfloxacin may interact with other medicines and supplements. Before taking norfloxacin, 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 norfloxacin could affect pregnancy or harm a fetus. Tell your health care provider if you are pregnant or plan to become pregnant. Your health care provider will let you know if you should take norfloxacin while you are pregnant or trying to get pregnant.

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

Interactions

Does norfloxacin interact with foods or drinks?

Norfloxacin should be taken on an empty stomach. Avoid taking norfloxacin within one hour before or two hours after a meal or dairy products (such as milk).

 

Norfloxacin may increase the effects of caffeine. It is best to limit eating or drinking things with caffeine (such as coffee or tea) while you are taking norfloxacin.

 

It is unknown if drinking alcohol will affect norfloxacin, but heavy drinking can slow your immune response and make it harder for your body to fight infections. The risk of dizziness may also increase if you drink alcohol while taking norfloxacin.

 

Does norfloxacin 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 norfloxacin.

  • Theophylline (Elixophyllin, Theo-24), which is a medicine for asthma or certain other breathing problems
  • An antipsychotic, which is a medicine for certain mental health conditions
  • Ropinirole, which is a medicine that may be used for Parkinson’s disease or restless legs syndrome (RLS)
  • A corticosteroid, such as dexamethasone, methylprednisolone, or prednisone, which is a medicine for certain inflammatory conditions
  • Tizanidine (Zanaflex), which is a muscle relaxant
  • Any product that contains caffeine, which is often found in medicines for reducing water weight (diuretics), staying awake, headaches, and hangover relief
  • Cyclosporine (Gengraf, Neoral, Sandimmune, and others), which is a medicine that suppresses your immune system
  • A medicine for diabetes
  • Probenecid, which is a medicine commonly used for gout
  • Nitrofurantoin (Macrobid, Macrodantin, and others), which is a medicine used to treat bladder infections
  • Sucralfate (Carafate), which is a medicine commonly used to treat ulcers in your stomach or intestines
  • Warfarin, which is a blood thinner
  • 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
  • An antacid, laxative, supplement, or vitamin containing aluminum, calcium, iron, magnesium, or zinc
  • Any medicine that can cause QT prolongation, which is a potentially dangerous heart rhythm problem
  • Erythromycin (Ery-Tab and others), which is a medicine used for bacterial infections
  • A tricyclic antidepressant, such as amitriptyline, nortriptyline, or protriptyline, even if it is not used for depression
  • A medicine used to control your heart rate or rhythm (antiarrhythmic), such as amiodarone, procainamide, quinidine, or sotalol
  • A diuretic, also called a water pill, which is a medicine used to reduce edema (fluid retention) and blood pressure

Norfloxacin may alter the blood levels of some other medicines. Tell your health care provider about all medicines that you take or have recently taken.

This may not be a complete list of medicines that can interact with norfloxacin. 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 norfloxacin?

If you or someone else has used too much norfloxacin, 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 norfloxacin?

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

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses.