Ciprofloxacin vs Doxycycline: Similarities, Differences, Uses, More

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Ciprofloxacin and doxycycline are two well-known antibiotics for many infections caused by harmful bacteria. Although these two drugs share many characteristics and have similar effectiveness and side effects, they are also distinctly different. This article compares and contrasts ciprofloxacin vs doxycycline, their uses, and drug interactions and provides other relevant information about these drugs.

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What Is Ciprofloxacin?

Ciprofloxacin is an effective broad-range antibiotic. It works by limiting the growth of harmful infection-causing bacteria. Common brand names of ciprofloxacin include Cipro, Cipro XR, and ProQuin XR.

Ciprofloxacin treats different types of bacterial infections of the skin, bones, renal, lungs, and more. It is commonly taken as oral tablets, extended-release tablets, oral powder, and intravenous (IV) solution). In addition, it is also available as eye drops, eye ointment, and ear drops.

Why Is Ciprofloxacin Prescribed?

Ciprofloxacin is prescribed as a treatment for bacterial infections, such as:

  • Chest or respiratory infections, including pneumonia and bronchitis
  • Skin and bone infections
  • Eye infections, like conjunctivitis and corneal ulcers of the eye
  • Ear infections, like swimmer’s ear or ear canal infections
  • Sexually transmitted diseases, such as gonorrhea
  • Typhoid fever
  • Infectious diarrhea caused by E. coli and Shigella bacteria

Ciprofloxacin is also prescribed to treat individuals exposed to inhalation anthrax or specific types of plague.

However, ciprofloxacin is generally prescribed as a last resort antibiotic for severe infections that do not respond to other antibiotic treatments.

This is because it falls under the fluoroquinolone group of antibiotics. Although effective, fluoroquinolone antibiotics are not routinely prescribed or used due to their high risk of severe side effects.

What Is Doxycycline?

Doxycycline is also a broad-range antibiotic. Unlike ciprofloxacin, it belongs to the tetracyclines group of antibiotics. It is sold under several popular brands, including Doryx, Vibramycin, and Oracea.

Doxycycline treats many bacterial infections, including bacterial acne and respiratory and urinary tract infections. It is a prescription-only antibiotic available in several forms, including tablets, capsules, oral suspension, and injections.

Why Is Doxycycline Prescribed?

Doxycycline is prescribed for a wide variety of bacterial infections and diseases. These include:

  • Respiratory tract infections, including sinusitis and pneumonia
  • UTIs
  • Skin infections and inflammatory skin conditions, like acne and rosacea
  • Malaria
  • Lyme disease
  • Uncomplicated gonococcal infections
  • Inclusion conjunctivitis
  • Escherichia coli or E.coli

Like ciprofloxacin, patients may also be prescribed doxycycline to treat anthrax and tularemia infections resulting from a bioterror attack.

Moreover, doxycycline is often prescribed as an alternative antibiotic for amoxicillin, especially for patients allergic to penicillin-type antibiotics.

Efficacy of Ciprofloxacin vs Doxycycline Against Infections

Both ciprofloxacin and doxycycline work well against a wide range of bacterial infections. Doxycycline has a few advantages, though. It can be used to treat more diseases and conditions than ciprofloxacin. Doxycycline is also relatively safer and has fewer significant side effects, which can affect the overall efficacy of the medication.

Despite its effectiveness, ciprofloxacin is typically only prescribed to patients whose conditions don’t improve after using other antibiotics for treatment. In addition, it is also prescribed to treat infections that cannot be treated by other safer alternative drugs.

One advantage of ciprofloxacin is that it can be better tolerated than doxycycline. In addition, compared to doxycycline, it carries a lower likelihood of antibiotic toxicity and developing antibiotic resistance.

Ciprofloxacin vs Doxycycline: Dosage Guidelines & Tips

When taking antibiotics, it is crucial to observe the dosage for the duration your doctor prescribed strictly. In addition, never extend your intake of any antibiotic without consulting a health care professional to avoid developing antibiotic resistance.

If you forget a dose, it is better to take the missed dose immediately. However, if it is almost time to take the next dose, it is best to forgo the missed dose and wait until the next scheduled medicine intake. For ciprofloxacin, skip taking your missed dose if it is less than six hours before your next one.

Ciprofloxacin Dosage

The recommended dosage of ciprofloxacin for adults is typically between 250 to 750 mg twice a day for immediate release tablets.

Doses are also adjusted lower for children and patients with kidney issues. In addition, for extended-release ciprofloxacin tablets, the dosage range is adjusted to between 500 to 1,000 mg once a day.

When using ciprofloxacin eye drops for conjunctivitis, the recommendation is one or two drops per affected eye every two hours. After following this for two days, patients can use one or two drops of the medication per eye every four hours for the following five days.

Oral liquid suspension ciprofloxacin must be shaken for about 15 seconds before measuring a dose. Using the provided dosing syringe or similar dose-measuring tool is best instead of a regular kitchen spoon.

Doxycycline Dosage

The general recommended doxycycline dosage for adults is 100 mg taken orally twice a day or 200 mg once daily. This applies to treating most conditions, such as sinusitis and UTIs.

For acne, dosage typically starts lower at 40 mg once daily, especially for delayed-release tablets or capsules. This can then be adjusted up to 100 mg twice daily based on the severity of the condition.

Some physicians may prescribe a loading dose of 200 mg on the first day of treatment, either as a single dose or in double doses across a 12-hour interval. For the following days of treatment, patients take 100 mg of doxycycline per day.

Ciprofloxacin vs Doxycycline: Considerations and Interactions

When using any medicine, there is always a chance it can interact with other medical issues.

Make sure to inform your physician of any pre-existing conditions you may have a history of or currently have.

For example, ciprofloxacin may reduce the amount of certain types of blood cells, which can increase the risk of bleeding and contacting other infections. In addition, although ciprofloxacin can be an effective treatment against gonorrhea, it is no longer recommended for the condition in the U.S. due to widespread resistance.

Doxycycline can potentially worsen vaginal candidiasis or yeast infections. Individuals with kidney issues should also use doxycycline with caution as the medicine’s side effects may be more substantial due to the slower removal of the drug from the body.

Drugs and Foods To Avoid While Taking Ciprofloxacin and Doxycycline

Taking other medications and eating certain foods while taking ciprofloxacin and doxycycline may cause adverse interactions or make the antibiotics less effective. As such, it is best practice to inform your physician regarding your regular diet and any medications, vitamins, or supplements you may be taking.


Ciprofloxacin has over 600 known drug interactions. This long list of medications to avoid include:

  • Aspirin
  • Albuterol
  • Ibuprofen
  • Prednisone
  • Tramadol
  • Metformin
  • Theophylline
  • Tizanidine
  • Warfarin and other anticoagulants
  • Didanosine powder or chewable tablets
  • Vitamins and supplements with calcium, iron, zinc, and magnesium
  • Antacids with aluminum, calcium, and magnesium

Patients prescribed ciprofloxacin are also advised to avoid food products containing caffeine, including coffee, tea, and energy drinks.

It is also best to avoid consuming dairy products and calcium-fortified foods alone when taking ciprofloxacin, as it may reduce the drug’s effectiveness. However, you can safely eat or drink dairy products when it is part of your meals.

11 drugs to avoid when using ciprofloxacin


Doxycycline has known drug interactions. These include penicillin and tretinoin. Therefore, taking these medications with doxycycline may affect its effectiveness or increase the risk of other illnesses.

In particular, using doxycycline with tretinoin for acne problems can increase the patient’s risk of developing pseudotumor cerebri, also known as “false brain tumor” or idiopathic intracranial hypertension.

Other medications that doctors may recommend avoiding while taking doxycycline include:

  • Aspirin
  • Amoxicillin
  • Ascorbic Acid
  • Cloxacillin
  • Isotretinoin
  • Drospirenone
  • Escitalopram
  • Benadryl
  • Magnesium Sulfate

Doxycycline also interacts with other drugs and supplements. For example, taking the following supplements may adversely affect how well doxycycline treats infections.

  • Antacids, especially those containing calcium, magnesium, and iron
  • Barbiturates
  • Carbamazepine
  • Phenytoin
  • Vitamins B12, C, and D3

Also, it is advisable to avoid drinking on doxycycline; when on the medication, avoid alcoholic beverages.

Ciprofloxacin and Doxycycline in Pregnancy and Breastfeeding

Many medications are contraindicated for pregnant women or women who are breastfeeding.

This is because some medicines may negatively affect the unborn fetus or breastfeeding baby. For example, ciprofloxacin and doxycycline both carry such warnings.

There are some exceptions in ciprofloxacin usage, even though it is not recommended for pregnant or breastfeeding women. Ciprofloxacin solution, such as ear or eye drops and Cipro eye ointment, is still generally safe to use during such times.

As for doxycycline, taking it while pregnant may cause adverse effects on the development of the unborn baby’s teeth and bones. In particular, taking doxycycline during the latter half of the pregnancy may result in the baby’s permanent yellowing or tooth discoloration.

Moreover, doxycycline treatments can significantly reduce the effectiveness of birth control pills. Therefore, patients are advised to consult their doctors regarding alternative, non-hormonal birth control options to prevent pregnancy during their doxycycline therapy.

Major Side Effects of Ciprofloxacin

As a fluoroquinolone antibiotic, ciprofloxacin carries a high risk of significant side effects, some of which may be disabling or irreversible.

A few of ciprofloxacin’s significant side effects are:

  • Tendon problems, including tendonitis and tendon rupture
  • Nerve damage, which can potentially be permanent
  • Significant mood swings or changes in behavior, even after a single dose
  • Extremely low blood sugar, which can cause patients to fall into a coma
  • Aorta or artery damage, which may cause internal bleeding or death

Other common yet less serious side effects of ciprofloxacin include:

  • Nausea
  • Vomiting
  • Diarrhea
  • Stomach pain
  • Fatigue
  • Muscle weakness
  • Headache
  • Jaundice, or discoloration (yellowing) of the skin or eyes
  • Abnormal liver function
  • Breathing problems
  • Sensitivity to sunlight
  • Faster heart rate

Major Side Effects of Doxycycline

Doxycycline has its share of severe side effects as well. However, the severity of its adverse effects falls well below that of ciprofloxacin.

Some of the most widespread side effects of doxycycline include an upset stomach, esophagus pain, and sensitivity to sunlight or photosensitivity. However, these can be managed relatively easily.

Taking doxycycline can also potentially cause throat thrush or oropharyngeal candidiasis in children and vaginal yeast infections in women.

Other side effects of taking doxycycline include:

  • Appetite loss
  • Nausea and vomiting
  • Bloody or persistent diarrhea
  • Dehydration
  • Fever and chills
  • Rashes or hives
  • High blood pressure in the skull
  • Blurry or double vision
  • Anemia
  • Pancreatitis

Patients may also experience discoloration of their teeth. For adults, this generally goes away soon after the doxycycline treatment stops. However, it can become permanent for babies whose mothers took doxycycline while pregnant or breastfeeding.

Frequently Asked Questions (FAQs)

It depends on the disease. For example, doctors may prescribe both antibiotics together to treat two different infections or a particularly resistant strain of bacteria. 

Taking Doxycycline and Ciprofloxacin together does not cause any adverse drug interactions. However, consider that combining antibiotics may prevent the two from working to their full potential.

Under normal circumstances, doxycycline may suppress some of the ciprofloxacin’s bacteria-killing abilities. 

Yes, you may. Make sure to consult your physician first and receive a prescription or recommendation. Taking any antibiotic outside its prescribed dosage or use may build up antibiotic resistance and make it harder to cure future infections. 

Doxycycline treats a wider variety of infections and diseases than ciprofloxacin. In addition, its effectiveness can be compared to penicillin. Therefore, it is often prescribed as an alternative antibiotic for patients allergic to penicillin-type antibiotics.

However, ciprofloxacin is generally better tolerated than doxycycline. In addition, compared to doxycycline, it has a lower risk of antibiotic toxicity and developing antibiotic resistance. 

Yes. Different antibiotics have varying effects on specific diseases, bacteria, and infections. However, make sure to only take two different types of antibiotics together after receiving a recommendation or prescription from your doctor. It is also vital to strictly follow the prescribed dosage and intake schedule to help prevent building antibiotic resistance.

The recommended substitute antibiotic for doxycycline will depend on the type of infection you need to treat. There are several comparable alternatives you may try. Among these are:

  • Amoxicillin or amoxicillin clavulanate
  • Ciprofloxacin
  • Azithromycin
  • Metronidazole
  • Sulfamethoxazole/trimethoprim
  • Minocycline

The content on Doctor Alexa’s blog is reviewed by Advanced practice registered nurses or pharmacist and is intended for educational purposes only. This information should not be relied upon as professional medical counsel. Be sure to always consult with your physician about the dangers and benefits of any medication, treatment or procedure.

You shouldn’t wait to see the doctor for simple health needs.