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Drug Info

Ciprofloxacin interactions to avoid

Ciprofloxacin interacts with various drugs and classes of drugs, which can result in complications
Karen Berger medical writer and reviewer headshot
By | Jan. 30, 2024
Three Rx pill bottles: Ciprofloxacin interactions to avoid

Key takeaways

  • Ciprofloxacin is a generic antibiotic used to treat various types of bacterial infections. 

  • Ciprofloxacin interacts with certain medications, such as duloxetine, tizanidine, warfarin, and others. 

  • Always tell your healthcare provider about your full medical history, as well as allergies to medications and all of the medicines you take, including prescription medicines, over-the-counter drugs, vitamins, and dietary supplements.

In this article:

Ciprofloxacin is a member of a drug class called fluoroquinolone or quinolone antibiotics. Ciprofloxacin is approved by the U.S. Food and Drug Administration (FDA) to treat various types of bacterial infections, such as pneumonia, urinary tract infections (UTIs), gonorrhea, anthrax, infectious diarrhea, skin structure infections, and infections of the bone, joint, stomach, and prostate, among others. 

Although ciprofloxacin can treat bronchitis, sinus infections, or UTIs, it should not be used for bronchitis, sinus infections, or certain types of UTIs if other treatment options are available. In pediatric patients (under 18 years of age), ciprofloxacin is only FDA approved for certain indications: complicated UTI, prevention of anthrax after exposure, and plague. This is due to the risk of serious adverse reactions.

Although ciprofloxacin treats bacterial infections, it does not work for viral infections such as the common cold or flu. Ciprofloxacin is a generic medication commonly known by the brand name Cipro. It is available in several formulations, such as immediate-release tablets (Cipro tablets), extended-release tablets (Cipro XR tablets), oral suspension (liquid), and by injection—as well as ear drops, eye drops, and eye ointment.

Some of the most common side effects of ciprofloxacin include:

  • Stomach problems like nausea, vomiting, abdominal pain, indigestion, and diarrhea
  • Pale skin
  • Extreme, unusual tiredness
  • Sleepiness
  • Vaginal itching and discharge

Some of the most serious side effects of ciprofloxacin include severe allergic reactions, skin reactions, tendonitis, tendon rupture, peripheral neuropathy, psychiatric reactions, severe diarrhea (antibiotic-associated diarrhea), liver damage, liver failure, and others. Ciprofloxacin has a boxed warning, the most serious warning required by the FDA, that outlines some of these serious side effects.

Ciprofloxacin interacts with various drugs, including Cymbalta (duloxetine), tizanidine, the blood thinner warfarin, and others. For those who take ciprofloxacin, it’s important to be aware of possible interactions that can affect the effectiveness of this antibiotic or cause other potential complications.

Ciprofloxacin drug interactions

Ciprofloxacin interacts with various drugs and classes of drugs, which can result in different complications.

Cymbalta (duloxetine)

Cymbalta (duloxetine) is a serotonin-norepinephrine reuptake inhibitor (SNRI) used to treat anxiety and depression. When combined with ciprofloxacin, an interaction may occur. Clinical studies have shown this could result in potentially being exposed to as much as five times as much duloxetine as usual. This could result in serious Cymbalta side effects and toxicity. The recommends that this combination be avoided. However, the patient should be closely monitored if the combination cannot be avoided.

Zanaflex (tizanidine)

Zanaflex is a skeletal muscle relaxant used to treat muscle spasms. Zanaflex should never be combined with ciprofloxacin due to an interaction that increases Zanaflex levels in the body. This can potentially cause serious problems like low blood pressure and extreme sedation. The prescribing information states that this combination of drugs should never be used together—the healthcare professional can select an appropriate alternative medication for either Zanaflex or ciprofloxacin. 

Warfarin 

Warfarin is a blood thinner that requires careful dosing and close monitoring to ensure the individual is clotting properly. Warfarin has many drug interactions, and ciprofloxacin is on the list. When taken with warfarin, ciprofloxacin can increase the risk of bleeding. In severe cases, this could be life-threatening. Many healthcare providers will avoid this combination unless no other alternative is available. If the combination must be prescribed, the patient will be closely monitored.

Drugs that increase the QT interval 

On an electrocardiogram (EKG), there is a measurement called the QT interval. If the QT interval becomes prolonged, it could result in arrhythmia (irregular heart rhythm), which could be dangerous or cause death. In rare cases, ciprofloxacin can cause a prolonged QT interval. Ciprofloxacin should not be used in people with (or are at risk for) a prolonged QT interval. It should not be used with certain drugs due to the risk of causing a prolonged QT interval. A different antibiotic should be used. Examples of interacting drugs include:

Oral diabetes medications

Ciprofloxacin can cause hypoglycemia (low blood sugar) when combined with certain oral diabetes drugs (diabetes medications that are taken by mouth). This hypoglycemia can be severe or even cause death. If ciprofloxacin is prescribed in combination with an oral diabetes medication, the patient should be closely monitored. This mostly occurs with drugs in a class called sulfonylureas, including the following drugs:

  • Amaryl (glimepiride)
  • Glyburide
  • Glipizide

Nonsteroidal anti-inflammatory drugs (NSAIDs)

NSAIDs are used to treat pain, inflammation, and fever. The ciprofloxacin prescribing information warns that when an NSAID is combined with a very high dose of a quinolone antibiotic, seizures have occurred. If you take an NSAID, consult your healthcare provider for medical advice. Although this interaction is not expected to occur with aspirin, other examples of NSAIDs include:

  • Advil, Motrin (ibuprofen)
  • Aleve (naproxen)
  • Celebrex (celecoxib)
  • Mobic (meloxicam)
  • Relafen (nabumetone)
  • Voltaren (diclofenac)

Drugs that decrease ciprofloxacin absorption

Certain drugs can decrease the body’s absorption of ciprofloxacin, making the antibiotic less effective. To avoid this problem, if you take one of the following medicines, you should take ciprofloxacin at least 2 hours before or 6 hours after you take the other medicine (you can also ask a healthcare provider or pharmacist if you need to help timing your medications):

  • Carafate (sucralfate)
  • Antacids like TUMS, Maalox, or Mylanta
  • Vitamins or supplements that contain calcium, iron, or zinc
  • Phosphate binders like Renagel (sevelamer) or Fosrenol (lanthanum)

Viagra, Revatio (sildenafil)

Sildenafil is also known as Viagra, which is used for erectile dysfunction (ED). Sildenafil is also available under the brand name Revatio, to treat pulmonary arterial hypertension (high blood pressure in the lungs). Combining ciprofloxacin with sildenafil can result in higher levels of sildenafil in the body, increasing the risk of serious side effects like dizziness or headache. If the combination is prescribed together, a lower dose of sildenafil may be prescribed, and careful monitoring is recommended. This interaction may also occur with other ED medications such as Levitra (vardenafil) or Stendra (avanafil), so check with your healthcare provider for medical advice.

Ambien (zolpidem)

Ambien (zolpidem), a medication used to help with sleeping, should not be used in combination with ciprofloxacin. The drugs could interact, resulting in increased levels of Ambien. This could cause worsened side effects and toxicity from Ambien.

Theophylline

Theophylline is a medication for treating asthma and chronic obstructive pulmonary disease (COPD). There have been reports of serious and fatal reactions in people who have taken theophylline with ciprofloxacin. Reactions have included cardiac arrest, seizures, status epilepticus, and respiratory failure. The combination of theophylline and ciprofloxacin should not be used together. However, close monitoring and a theophylline dosage adjustment may be required if the combination cannot be avoided.

Other ciprofloxacin drug interactions

Additionally, some other notable drug interactions with ciprofloxacin include:

  • Veozah (fezolinetant): Veozah is used to treat hot flashes associated with menopause. This medication should never be used with ciprofloxacin because it could result in dangerously high levels of (and toxicity from) Veozah.
  • Addyi (flibanserin): Addyi is used to treat premenopausal women with hypoactive sexual desire disorder. This medication should never be used with ciprofloxacin because it could result in severely low blood pressure and fainting. 
  • Dilantin (phenytoin): Dilantin is a medication that prevents and controls seizures. The ciprofloxacin prescribing information recommends using the combination of ciprofloxacin and Dilantin with caution, as unpredictable levels of Dilantin may result. Too-low levels of Dilantin could affect seizure control, increasing the risk of seizures—or, on the other hand, too-high levels can cause a Dilantin overdose. If the combination is prescribed, the patient will be closely monitored during and shortly after ciprofloxacin treatment. 
  • Cyclosporine: Cyclosporine is a medication used to prevent rejection after an organ transplant. It can also treat rheumatoid arthritis (RA) or psoriasis. Combining ciprofloxacin and cyclosporine may cause kidney problems, so if this combination is prescribed together, the patient will be closely monitored. 
  • Methotrexate: Methotrexate is used to treat certain types of cancers. It can also treat RA or psoriasis. The ciprofloxacin prescribing information notes that combining ciprofloxacin and methotrexate could increase levels of methotrexate in the body. This could lead to toxic reactions. If the combination is prescribed together, close monitoring will be required.
  • Ropinirole: Ropinirole is used to treat Parkinson’s disease as well as restless legs syndrome. Combining this medication with ciprofloxacin could potentially result in increased levels of ropinirole in the body, increasing the risk of side effects. If the combination is prescribed together, close monitoring and a dosage adjustment will be required.
  • Clozaril (clozapine): Clozaril, a medication used in people with schizophrenia, can interact with ciprofloxacin. The resulting effect can be increased levels of clozapine in the body and increased side effects. If the combination is prescribed together, close monitoring and a dosage adjustment will be required.
  • Probenecid: Probenecid is a medication used to treat gout or gouty arthritis. Combining probenecid with ciprofloxacin can result in a higher level of Cipro, which can cause side effects and toxicity. If the combination is prescribed together, close monitoring will be required.

Ciprofloxacin and medical conditions

Ciprofloxacin is not safe for everyone to take. Contraindications of Cipro (situations where you should not take this medication) include people who:

  • Are allergic to ciprofloxacin or any type of fluoroquinolone medication (such as levofloxacin or moxifloxacin), or any ingredient in the medication
  • Take certain medications such as Zanaflex (tizanidine) or Veozah
  • Have a history of myasthenia gravis
  • Have a history of aortic aneurysm or are at greater risk for aortic aneurysm (ciprofloxacin will only be prescribed if no other options are available)
  • Are breastfeeding (consult your healthcare provider for medical advice if you are pregnant)
  • Have long QT syndrome (or are at risk for long QT syndrome), or you take certain medications that can affect the QT interval 

Ciprofloxacin and sun exposure

While taking ciprofloxacin, your skin can be more sensitive to sun or UV light, which can result in a sunburn-like reaction. Symptoms may include burning skin, redness, blistering, oozing, and swelling. While taking ciprofloxacin, avoid sunlight or ultraviolet light (such as tanning beds) as much as possible. While outside, wear sunscreen, protective clothing, sunglasses, and a hat.

Ciprofloxacin and caffeine 

An interaction may occur between ciprofloxacin and caffeine that can increase the levels and effects of caffeine (such as nervousness, insomnia, heart pounding, and anxiety). This may occur with:

  • Caffeine in your diet, such as coffee, tea, soda, chocolate, energy drinks
  • Caffeine supplements, such as “stay awake,” or alertness aids like Vivarin or NoDoz
  • Medications that contain caffeine, such as Excedrin Migraine or Fioricet

If you consume caffeine in your diet or take medication or a supplement that contains caffeine, consult your healthcare provider before using ciprofloxacin.

Ciprofloxacin and dairy products

Because of the calcium interaction, you should not take ciprofloxacin with dairy products (or juices that contain calcium) alone. You can, however, take ciprofloxacin with a meal that contains dairy or calcium-fortified juices.

How to minimize ciprofloxacin interactions

Although ciprofloxacin has some potential interactions, in many cases, it can still be taken safely with some precautions. 

Always consult your healthcare provider before beginning a new medicine. Before you start taking ciprofloxacin, make your provider aware of all of your medical conditions, especially if you: 

  • Are pregnant or trying to become pregnant
  • Are breastfeeding 
  • Have problems with your bones, joints, or tendons
  • Have numbness and tingling of the fingers and toes or any type of nerve condition
  • Have heart problems, including heart disease, high blood pressure, or irregular heartbeat
  • Have a history of hypokalemia (low potassium levels)
  • Have diabetes
  • Have liver or kidney disease
  • Have any mental health conditions
  • Have myasthenia gravis
  • Have seizures
  • Have had a reaction to ciprofloxacin or any type of antibiotic

Tell your physician about all your medicines, including prescription and OTC drugs, vitamins, supplements, or herbal products. While taking ciprofloxacin, do not start any new medication unless your healthcare provider approves.

Your healthcare provider may need to change your medicine or adjust the dose of ciprofloxacin—or another medicine—in case of a potential drug interaction. 

Always take your medication as directed by your healthcare provider. Since ciprofloxacin is an antibiotic, you should finish the full course of ciprofloxacin as prescribed. Doing so helps clear the infection and prevent antibiotic resistance. Exceptions to this will be if your doctor tells you to discontinue this medicine or if you have an allergic or skin reaction, which could be life-threatening. Signs of an allergic reaction may include hives, difficulty swallowing or breathing, or swelling of the face, lips, tongue, or throat. Symptoms of a skin reaction may include fever, sore throat, burning eyes, skin pain, rash, and blistering or peeling skin. If you have any of these symptoms, get emergency medical help immediately. 

When to talk to a healthcare provider about ciprofloxacin interactions

This article outlines various ciprofloxacin interactions but is not a complete list of every potential interaction. Tell your healthcare provider about all your medical conditions and medications, including prescription medicines, over-the-counter (OTC) drugs or nonprescription medications, vitamins, and dietary supplements. Doing so helps ensure proper management and monitoring of your medical condition. 

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