Cipro vs. Flagyl: Side Effects Differences, Uses, and Dosage

  • Medical Reviewer: John P. Cunha, DO, FACOEP
    John P. Cunha, DO, FACOEP

    John P. Cunha, DO, FACOEP

    John P. Cunha, DO, is a U.S. board-certified Emergency Medicine Physician. Dr. Cunha's educational background includes a BS in Biology from Rutgers, the State University of New Jersey, and a DO from the Kansas City University of Medicine and Biosciences in Kansas City, MO. He completed residency training in Emergency Medicine at Newark Beth Israel Medical Center in Newark, New Jersey.

Cipro vs. Flagyl Differences

What is Cirpo? What is Flagyl? How do they work?

Ciprofloxacin is a fluoroquinolone antibiotic used to treat many types of bacterial infections. It is used to treat acute sinusitis, bone and joint infections, chronic bacterial prostatitis, infectious diarrhea, as empirical therapy in febrile neutropenic patients, intra-abdominal infections, lower respiratory tract infections, lung infections, chronic bronchitis, nosocomial pneumonia, skin/skin structure infections, urinary tract infections, urethral and cervical gonococcal infections, anthrax infection, intra-abdominal infections, typhoid fever, cervical and urethral gonorrhea, acute uncomplicated cystitis, and pneumonic and septicemic plague.

Flagyl is an antibiotic effective against anaerobic bacteria and certain parasites. It is used to treat anaerobic bacterial infections, sexually transmitted diseases, bacterial vaginosis, colorectal surgical infection, abscesses in the liver/pelvis/abdomen, C. difficile diarrhea, and acne rosacea. It also is used to treat parasitic infections including trichomoniasis, amebiasis, and Gardnerella infection. Flagyl also may be used in combination with other drugs to treat H. pylori infection that causes stomach or intestinal ulcers.

What are the uses for Cipro vs. Flagyl?

Cipro uses

Doctors and other medical health-care professionals prescribe Cipro and Cipro XR to treat bacterial infections, for example:

  • Skin infections
  • Lung or airway Infections, for example, TB (tuberculosis), pneumonic and septicemic plague due to Yersinia pestis (Y. pestis), lower respiratory tract infections, and chronic bronchitis)
  • Bone infections
  • Joint infections
  • Urinary tract infections (UTI) caused by certain bacteria such as E. coli.
  • Infectious diarrheas caused by E. coli, Campylobacter jejuni, and Shigella bacteria.
  • Anthrax patients with fever and low white blood cell counts, and intra-abdominal infections.
  • Typhoid fever
  • Cervical and urethral gonorrhea due to Neisseria gonorrhoeae
  • Chronic bacterial prostatitis
  • Acute uncomplicated cystitis

Flagyl uses

  • Flagyl is used to treat parasitic infections including Giardia infections of the small intestine, amebic liver abscess, and amebic dysentery (infection of the colon causing bloody diarrhea), bacterial vaginosis, trichomonas vaginal infections, and carriers of trichomonas (both sexual partners) who do not have symptoms of infection.
  • Flagyl is also used alone or in combination with other antibiotics in treating abscesses in the liver, pelvis, abdomen, and brain caused by susceptible anaerobic bacteria.
  • Flagyl is also used in treating infection of the colon caused by a bacterium called C. difficile. Many commonly-used antibiotics can alter the type of bacteria that inhabit the colon. C. difficile is an anaerobic bacterium that can infect the colon when the normal types of bacteria in the colon are inhibited by common antibiotics. This leads to inflammation of the colon (pseudomembranous colitis) with severe diarrhea and abdominal pain.)
  • Flagyl also is used in combination with other drugs to treat Helicobacter pylori (H. pylori) that causes stomach or intestinal ulcers.
  • Flagyl topical gel is used for treating acne rosacea.
  • Flagyl vaginal gel is used for treating bacterial vaginosis.

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What are the side effects of Cirpo vs. Flagyl?

Cipro side effects

Warning: Serious adverse reactions of this Cipro

Cipro and Cipro XR as well as other antibiotics in the fluoroquinolone class of antibiotics has been associated with tendonitis and even tendon rupture, particularly the Achilles tendon. Some doctors and other medical professionals recommend that their patients discontinue vigorous exercise while they are taking fluoroquinolone antibiotics.

Fluoroquinolones have neuromuscular blocking activity and can worsen muscle weakness in individuals with myasthenia gravis.

The most common side effects of Cipro, Cipro XR are:

Symptoms of shock include:

Cipro serious side effects and adverse events

Possible serious side effects of Cipro, Cipro XR include:

Other serious side effects and adverse events of Cipro, Cipro XR include:

  • Cipro, Cipro XR should be used with caution in patients with central nervous system diseases such as seizures, because rare seizures have been reported in patients receiving Cipro, Cipro XR.
  • Cipro, Cipro XR should be avoided in children and adolescents less than 18 years of age, as safe use in these patients has not been established.
  • Many antibiotics, including Cipro, Cipro XR, can alter the normal bacteria in the colon and encourage overgrowth of a bacterium responsible for the development of inflammation of the colon, (C. difficile or pseudomembranous colitis). Patients who develop signs of pseudomembranous colitis after starting Cipro, Cipro XR (diarrhea, fever, abdominal pain, and possibly shock) should contact their doctor immediately.
  • Cardiac arrest
  • Respiratory failure

Flagyl side effects

Flagyl is a useful antibiotic and is generally well tolerated with appropriate use.

The most common and minor side effects include:

Side effects that are uncomfortable, but may become serious include:

  • Brain disease
  • Fevers
  • Mouth sores
  • Pain with urination
  • Prickling or tingling sensations that may become permanent
  • Cystitis
  • Pelvic pain or pressure
  • Decrease of libido
  • Proctitis
  • Stomitis
  • Glossitis

Serious side effects of Flagyl

Serious side effects of Flagyl are rare and the drug should be stopped if these symptoms appear:

What is the dosage of Cipro vs. Flagyl?

Cipro dosage

  • For most infections the recommended oral dose for adults is 250-750 mg (immediate release tablets) every 12 hours or 500-1000 mg (extended release tablets) every 24 hours.
  • The usual intravenous dose is 200-400 mg every 8-12 hours.

Flagyl dosage

  • Metronidazole may be taken orally with or without food.
  • In the hospital, metronidazole can be administered intravenously to treat serious infections.
  • The liver is primarily responsible for eliminating metronidazole from the body, and doses may need to be reduced in patients with liver disease and abnormal liver function.

Various metronidazole regimens are used. Some examples are listed below.

  • Amebic dysentery: 750 mg orally 3 times daily for 5-10 days
  • Amebic liver abscess: 500-750 mg orally three times daily for 5-10 days
  • Anaerobic infections: 7.5 mg/kg orally or by injection every 6 hours for 7 to 10 days not to exceed 4 grams daily.
  • Bacterial vaginosis: 750 mg (extended release tablets) once daily for 7 days or 500 mg twice daily for 7 days or 2 g single dose or one applicator-full of 0.75% vaginal gel, once or twice daily for 5 days.
  • Clostridium difficile infection: 250-500 mg orally 4 times daily or 500-750 orally 3 times daily
  • Giardia: 250 mg orally three times daily for 5 days Helicobacter pylori: 800-1500 mg orally daily for several days in combination with other drugs.
  • Pelvic inflammatory disease (PID): 500 mg orally twice daily for 14 days in combination with other drugs.
  • Trichomoniasis: 2 g single dose or 1 g twice
  • Rosacea: apply topical gel 0.75-1% once daily

What drug interactions occur with Cipro vs. Flagyl?

Cipro drug interactions

  • Ciprofloxacin administered together with theophylline (Respbid, Slo-Bid, Theo-24, Theolair) can lead to elevated, toxic blood levels of theophylline. Theophylline is used to open airways in the treatment of asthma. Toxic levels of theophylline can lead to seizures, and disturbances in heart rhythm. If concurrent use of ciprofloxacin and theophylline cannot be avoided, frequent blood tests to monitor theophylline blood levels are recommended.
  • Ciprofloxacin increases the effect of tizanidine (Zanaflex) that is used to treat muscle spasticity. Therefore, the two drugs should not be combined.
  • Iron salts (for example, ferrous sulfate) may reduce the absorption of ciprofloxacin because of formation of a ciprofloxacin-iron complex that is not absorbable. Antacids also may reduce the absorption of ciprofloxacin. If patients are receiving iron salts or antacids and ciprofloxacin, the ciprofloxacin should be given two hours before or six hours after the iron salt or antacid.
  • Ciprofloxacin may increase the blood thinning effect of warfarin (Coumadin, Jantoven). The reason for this is unknown. Anticoagulant activity should be monitored after starting or stopping ciprofloxacin.
  • Sevelamer (Renagel) may reduce the absorption of ciprofloxacin and possibly reduce the effectiveness of ciprofloxacin. Milk and orange juice also may reduce the absorption of ciprofloxacin. Ciprofloxacin, as with iron and antacids, should be given two hours before or six hours after milk or orange juice.
  • Administration of ciprofloxacin with diabetic medications (for example glyburide [Micronase, Diabeta, Glynase, Prestab]) may lead to severe low blood glucose.
  • Ciprofloxacin may increase blood concentrations of sildenafil (Viagra) that is used for treating erectile dysfunction. This combination should be avoided if possible.
  • Patients taking Cipro, Cipro XR can develop sensitivity of the skin to direct sunlight (photosensitivity) and should avoid exposure to sunlight or use sunblock.
  • Fluoroquinolones worsen low blood glucose levels when combined with sulfonylureas, for example, glyburide (Micronase, Diabeta, Glynase, Prestab).

Flagyl drug interactions

  • Alcohol should be avoided because metronidazole and alcohol together can cause severe nausea, vomiting, cramps, flushing, and headache.
  • Metronidazole can increase the blood thinning effects of warfarin (Coumadin, Jantoven) and increase the risk of bleeding probably by reducing the breakdown of warfarin.
  • Cimetidine (Tagamet) increases blood levels of metronidazole while cholestyramine (Questran, Questran Light) reduces blood levels of metronidazole by reducing its absorption.
  • Metronidazole should not be combined with amprenavir (Agenerase) for treating human immunodeficiency disease (infection with HIV) because amprenavir contains propylene glycol.
  • Metronidazole blocks the breakdown of propylene glycol in the liver leading to accumulation of propylene glycol in blood. Accumulation of propylene glycol could cause seizures, increased heart rate, and lead to kidney failure.
  • Metronidazole increases the blood levels of carbamazepine (Tegretol, Tegretol XR, Equetro, Carbatrol), lithium (Eskalith, Lithobid) and cyclosporine though unknown mechanisms. Serious reactions may occur if these drugs are taken with metronidazole.

Are Cipro and Flagyl safe to take if I'm pregnant or breastfeeding?

  • Doctors suggest that should not use Cipro if you are pregnant or breastfeeding because they do not know if it is safe.
  • Flagyl is not used in early pregnancy because of potential adverse effects on the fetus. Metronidazole is excreted in breast milk. Females who are nursing, because of potential adverse effects on the newborn, should not use metronidazole.

Summary

Cipro, generic name ciprofloxacin, is an antibiotic that belongs to a class of antibiotics called fluoroquinolones, prescribed for the treatment a variety of bacterial infections. Flagyl, generic name metronidazole, is an antibiotic prescribed for the treatment of parasites and anaerobic bacteria.

Cipro and Flagyl have the same common side effects like rash, headache, abdominal cramps and/or pain, diarrhea, nausea, and vomiting.

Nerve pain (peripheral neuropathy) and seizures are serious side effects of both Cipro and Flagyl. Cipro may cause rupture of the Achilles tendon. Cipro may cause a rare allergic reaction called anaphylaxis or shock. Symptoms of shock include shortness of breath, hives, itching, and cardiovascular collapse.

Examples of side effects unique to Flagyl are dizziness, constipation, vaginal dryness, furry tongue, dry mouth, and loss of appetite. Neither Cipro or Flagyl are recommended during pregnancy or while breastfeeding.

Treatment & Diagnosis

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Medically Reviewed on 10/3/2017
References
REFERENCES:

FDA Prescribing Information.

Medscape. metronidazole (Rx).
<https://reference.medscape.com/drug/flagyl-metronidazole-342566>

Medscape. ciprofloxacin. (Rx).
< https://reference.medscape.com/drug/cipro-xr-ciprofloxacin-342530 >

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