Quinolones – Types, Side Effects, Interactions

Last updated: February 8, 2026Reviewed date: February 8, 2026Reading time: 6 min read
Patient Tools

Read, save, and share this guide

Use these quick tools to make this medical article easier to read, print, save, or share with a family member.

Patient Mode

Understand this article easily

Switch between simple English and easy Bangla patient notes. This is for education and does not replace a doctor consultation.

Quinolone antibiotic is any member of a large group of broad-spectrum bactericides that share a bicyclic core structure related to the compound 4-quinolone. They are used in human and veterinary medicine to treat bacterial infections, as well as in animal husbandry. Nearly all quinolone antibiotics in modern use are fluoroquinolones, which contain a fluorine atom in...

For severe symptoms, danger signs, pregnancy, child illness, or sudden worsening, seek urgent medical care.

বাংলা রোগী নোট এখনো যোগ করা হয়নি। পোস্ট এডিটরে “RX Bangla Patient Mode” বক্স থেকে সহজ বাংলা সারাংশ যোগ করুন।

এই তথ্য শিক্ষা ও সচেতনতার জন্য। এটি ডাক্তারি পরীক্ষা, রোগ নির্ণয় বা প্রেসক্রিপশনের বিকল্প নয়।

Article Summary

Quinolone antibiotic is any member of a large group of broad-spectrum bactericides that share a bicyclic core structure related to the compound 4-quinolone. They are used in human and veterinary medicine to treat bacterial infections, as well as in animal husbandry. Nearly all quinolone antibiotics in modern use are fluoroquinolones, which contain a fluorine atom in their chemical structure and are effective against both Gram-negative and Gram-positive bacteria. One example is ciprofloxacin, one of the most widely used antibiotics worldwide. Types...

Key Takeaways

  • This article explains Types of Quinolone in simple medical language.
  • This article explains Types  of Quinolone in simple medical language.
  • This article explains Mechanism of Action of Quinolone in simple medical language.
  • This article explains Indications of Quinolone in simple medical language.
Educational health guideWritten for patient understanding and clinical awareness.
Reviewed content workflowUse writer and reviewer profiles for stronger trust.
Emergency safety firstUrgent warning signs are highlighted below.
Choose your reading view

Patient View highlights a simple learning journey. Clinical View reveals structure, evidence, and editorial completeness.

Seek urgent medical care if you notice

These warning signs are general safety guidance. Local emergency numbers and clinical judgment should always come first.

  • Severe symptoms, breathing difficulty, fainting, confusion, or rapidly worsening illness.
  • New weakness, severe pain, high fever, or symptoms after a serious injury.
  • Any symptom that feels urgent, unusual, or unsafe for the patient.
1

Emergency now

Use emergency care for severe, sudden, rapidly worsening, or life-threatening symptoms.

2

See a doctor

Book a professional medical evaluation if symptoms persist, worsen, recur often, affect daily activities, or occur in a high-risk patient.

3

Learn safely

Use this article to understand possible causes, tests, treatment options, prevention, and questions to ask your clinician.

Before reading

RX Patient Tools

Use these quick guides before reading the article, or return to them when you need help preparing questions for a doctor.

Start here Choose the right pathway for symptoms, reports, medicines, or urgent warning signs. Disease article roadmap Read this topic step by step: meaning, symptoms, warning signs, diagnosis, treatment, prevention, and follow-up. Treatment planner Prepare questions about treatment choices, benefits, risks, side effects, and follow-up. Family & caregiver guide Organize symptoms, reports, medicines, questions, and follow-up safely. Nutrition & diet guide Prepare food, hydration, supplement, and medicine-timing questions safely. Prevention guide Organize risk factors, protective habits, screening, and warning signs. Recovery guide Prepare a safe plan for activity, rehabilitation, warning signs, and follow-up.
Definition

Quinolone bacterial infections. সহজ বাংলা: ব্যাকটেরিয়ার সংক্রমণের ওষুধ।" data-rx-term="antibiotic" data-rx-definition="An antibiotic is a medicine used to treat bacterial infections. সহজ বাংলা: ব্যাকটেরিয়ার সংক্রমণের ওষুধ।">antibiotic is any member of a large group of broad-spectrum bactericides that share a bicyclic core structure related to the compound 4-quinolone. They are used in human and veterinary medicine to treat bacterial infections, as well as in animal husbandry. Nearly all quinolone antibiotics in modern use are fluoroquinolones, which contain a fluorine atom in their chemical structure and are effective against both Gram-negative and Gram-positive bacteria. One example is ciprofloxacin, one of the most widely used antibiotics worldwide.

Types of Quinolone

First-generation

  • flumequine
  • oxolinic acid
  • rosoxacin

Structurally related first-generation drugs, but formally not 4-quinolones, include cinoxacin, nalidixic acid, and piromidic acid, pipemidic acid

Second generation

The second-generation class is sometimes subdivided into “Class 1” and “Class 2”.

  • ciprofloxacin 
  • fleroxacin
  • lomefloxacin 
  • nadifloxacin
  • norfloxacin
  • ofloxacin 
  • pefloxacin
  • rufloxacin

A structurally related second-generation drug, but formally not a 4-quinolone, is enoxacin

Third generation

Unlike the first and second generations, the third generation is active against streptococci.

  • balofloxacin
  • grepafloxacin
  • levofloxacin 
  • pazufloxacin
  • sparfloxacin 
  • temafloxacin

A structurally related third-generation drug, but formally not a 4-quinolone, is tosufloxacin

Fourth generation

Fourth-generation fluoroquinolones act at DNA gyrase and topoisomerase IV. This dual action slows development of resistance.

  • clinafloxacin
  • gatifloxacin 
  • moxifloxacin
  • sitafloxacin
  • prulifloxacin
  • besifloxacin

Two structurally related third generation drugs, but formally not 4-quinolones, are gemifloxacin  and trovafloxacin

Types  of Quinolone

1st generation

  • Cinoxacin
  • Flumequine
  • Nalidixic acid
  • Oxolinic acid
  • Pipemidic acid
  • Piromidic acid
  • Rosoxacin

2nd generation

  • Ciprofloxacin
  • Ofloxacin
  • Enoxacin
  • Fleroxacin
  • Lomefloxacin
  • Nadifloxacin
  • Norfloxacin
  • Pefloxacin
  • Rufloxacin

3rd generation

  • Levofloxacin
  • Balofloxacin
  • Grepafloxacin
  • Pazufloxacin
  • Sparfloxacin
  • Temafloxacin
  • Tosufloxacin

4th generation

  • Besifloxacin
  • Delafloxacin
  • Gatifloxacin
  • Finafloxacin
  • Gemifloxacin
  • Moxifloxacin
  • Clinafloxacin
  • Garenoxacin
  • Prulifloxacin
  • Sitafloxacin
  • Trovafloxacin/Alatrofloxacin

Vet.

  • Danofloxacin
  • Difloxacin
  • Enrofloxacin
  • Ibafloxacin
  • Marbofloxacin
  • Orbifloxacin
  • Pradofloxacin
  • Sarafloxacin

Mechanism of Action of Quinolone

The bactericidal action of ciprofloxacin results from inhibition of the enzymes topoisomerase II (DNA gyrase) and topoisomerase IV, which are required for bacterial DNA replication, transcription, repair, strand supercoiling repair, and recombination.
The mechanism by which ciprofloxacin’s inhibition of DNA gyrase or topoisomerase IV results in death in susceptible organisms has not been fully determined. Unlike beta-lactam anti-infectives, which are most active against susceptible bacteria when they are in the logarithmic phase of growth, studies using Escherichia coli and Pseudomonas aeruginosa indicate that ciprofloxacin can be bactericidal during both logarithmic and stationary phases of growth; this effect does not appear to occur with gram-positive bacteria (e.g., Staphylococcus aureus). In vitro studies indicate that ciprofloxacin concentrations that approximate the minimum inhibitory concentration (MIC) of the drug induce filamentation in susceptible organisms; high concentrations of the drug result in enlarged or elongated cells that may not be extensively filamented. Although the bactericidal effect of some fluoroquinolones (e.g., norfloxacin) evidently requires competent RNA and protein synthesis in the bacterial cell, and concurrent use of anti-infectives that affect protein synthesis (e.g., chloramphenicol, tetracyclines) or RNA synthesis (e.g., rifampin) inhibit the in vitro bactericidal activity of these drugs, the bactericidal effect of ciprofloxacin is only partially reduced in the presence of these anti-infectives. This suggests that ciprofloxacin has an additional mechanism of action that is independent of RNA and protein synthesis.

Indications of Quinolone

  • Upper/Lower respiratory tract infection  (respiratory, skin, soft tissue, UTI, ENT)
  • Infectious diarrheas caused by E. coli, Campylobacter jejuni, and Shigella bacteria.
  • 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 and Joint Infections
  • Anthrax patients with fever and low white blood cell counts, and intra-abdominal infections.
  • Acute bacterial otitis media
  • Skin and skin structure infections
  • Urinary tract infections
  • Uncomplicated gonorrhea
  • Pelvic inflammatory disease
  • Bacterial septicemia
  • Intra-abdominal infections
  • Pelvic Inflammatory Disease
  • Meningitis
  • Osteomyelitis
  • Pelvic Inflammatory Disease
  • Surgical prophylaxis
  • Community-acquired pneumonia
  • Acute otitis media
  • Intra-abdominal infections
  • Complicated urinary tract infections (including pyelonephritis)
  • Infections of bones and joints
  • Complicated skin and soft tissue infections
  • Gonorrhea
  • Syphilis
  • Bacterial Endocarditis.
  • Meningococcal Meningitis Prophylaxis
  • Salmonella Enteric Fever
  • Salmonella Gastroenteritis
  • Community-acquired pneumonia
  • Hospital-acquired pneumonia
  • Acute otitis media
  • Intra-abdominal infections
  • Complicated urinary tract infections (including pyelonephritis)
  • Infections of bones and joints
  • Complicated skin and soft tissue infections
  • For treatment of acute exacerbations of chronic obstructive pulmonary disease in adults
  • For treatment of disseminated Lyme borreliosis (early (stage II) and late (stage III)) in adults and children including neonates from 15 days of age.
    |For Pre-operative prophylaxis of surgical site infections

Side Effects of Quinolone

Most common

More common

Rare

Drug Interactions of Quinolone

Fluoroquinolones may interact with following drugs, supplements, & may change the efficacy of drugs

References

Quinolones – Types, Side Effects, Interactions

RX Clinical Pathway Engine

Continue through a complete learning pathway

Move from understanding the topic to symptoms, tests, treatment, medicines, monitoring, and prevention.

Search the complete library
  1. Understand the condition Begin with the essential facts and a clear explanation of the topic.
  2. Recognize symptoms Learn common symptoms, signs, and patterns of presentation.
  3. Know when to seek help Review urgent warning signs and when professional assessment may be needed.
  4. Understand causes and risks Explore causes, risk factors, mechanisms, and contributing conditions.
  5. Explore tests and diagnosis Learn how clinicians assess the condition and which investigations may be discussed.
  6. Learn treatment approaches Review general treatment categories and management principles.
  7. Understand medicines safely Continue to medicine education, uses, precautions, and monitoring.
  8. Plan monitoring and follow-up Understand monitoring, complications, rehabilitation, and follow-up learning.
  9. Review prevention and self-care Explore prevention, healthy routines, and questions to discuss with a clinician.

Conditions & Diseases

Background, symptoms, causes, diagnosis, and care.

Explore this library

Tests & Investigations

Laboratory, imaging, screening, and diagnostic education.

Explore this library

Medicines

Uses, safety, monitoring, and related medicine knowledge.

Explore this library

Cancer Knowledge

Cancer types, screening, oncology, and treatment education.

Explore this library
Doctor visit helper

Prepare before seeing a doctor

A simple rural-patient checklist to help you explain symptoms clearly, ask better questions, and avoid unsafe self-treatment.

Safety note: This is not a prescription or diagnosis. For severe symptoms, pregnancy danger signs, children with serious illness, chest pain, breathing difficulty, stroke-like weakness, or major injury, seek urgent care.

Which doctor may help?

Start with a registered doctor or the nearest qualified health center.

What to tell the doctor

  • Write when the problem started and how it changed.
  • Bring old prescriptions, investigation reports, and current medicines.
  • Write allergies, pregnancy status, diabetes, kidney/liver disease, and major past illnesses.
  • Bring one family member if the patient is weak, elderly, confused, or a child.

Questions to ask

  • What is the most likely cause of my symptoms?
  • Which danger signs mean I should go to hospital quickly?
  • Which tests are necessary now, and which can wait?
  • How should I take medicines safely and what side effects should I watch for?
  • When should I come for follow-up?

Tests to discuss

  • Vital signs: temperature, pulse, blood pressure, oxygen saturation
  • Basic physical examination by a clinician
  • CBC, urine test, blood sugar, or imaging only when clinically needed

Avoid these mistakes

  • Do not use antibiotics, steroid tablets/injections, or strong painkillers without proper medical advice.
  • Do not hide pregnancy, kidney disease, ulcer, allergy, or blood thinner use.
  • Do not delay emergency care when danger signs are present.

Medicine safety and first-aid guide

This section is for patient education only. It does not replace a doctor, pharmacist, or emergency care.

Safe first steps

  • Avoid heavy lifting, sudden bending, and prolonged bed rest.
  • Use comfortable posture and gentle movement as tolerated.
  • Discuss physiotherapy, X-ray, or MRI only when clinically needed.

OTC medicine safety

  • For mild back pain, pain-relief medicine may be discussed with a doctor or pharmacist.
  • Avoid repeated painkiller use if you have kidney disease, stomach ulcer, uncontrolled blood pressure, or are taking blood thinners.

Avoid these mistakes

  • Do not start antibiotics without a proper medical decision.
  • Do not use steroid tablets or injections casually for quick relief.
  • Do not delay emergency care because of home remedies.

Get urgent help if

  • Back pain with leg weakness, numbness around private area, loss of urine/stool control, fever, cancer history, or major injury needs urgent care.
Medicine names, dose, and timing must be decided by a qualified clinician or pharmacist after checking age, pregnancy, allergy, other diseases, and current medicines.

For rural patients and family caregivers

Patient health record and symptom diary

Write your symptoms, medicines already taken, test results, and questions before visiting a doctor. This note stays on your device unless you print or copy it.

Doctor to discuss: Orthopedic / spine specialist, physical medicine doctor, or qualified clinician
Tests to discuss with doctor
  • Neurological examination for leg power, sensation, reflexes, and straight leg raise
  • X-ray only if injury, deformity, long-lasting pain, or doctor suspects bone problem
  • MRI discussion if severe nerve symptoms, weakness, bladder/bowel problem, or persistent symptoms
Questions to ask
  • What is the most likely cause of my symptoms?
  • Which warning signs mean I should go to emergency care?
  • Which tests are really needed now?
  • Which medicines are safe for my age, pregnancy status, allergy, kidney/liver/stomach condition, and current medicines?
  • Is physiotherapy, posture correction, or activity modification needed?

Emergency warning signs such as chest pain, severe breathing difficulty, sudden weakness, confusion, severe dehydration, major injury, or loss of bladder/bowel control need urgent medical care. Do not wait for online information.

Safe pathway to proper treatment

Care roadmap for: Quinolones – Types, Side Effects, Interactions

Use this simple roadmap to understand the next safe steps. It is educational and does not replace examination by a doctor.

Go to emergency care if you notice:
  • Severe or rapidly worsening symptoms
  • Breathing difficulty, chest pain, fainting, confusion, severe weakness, major injury, or severe dehydration
Doctor / service to discuss: Qualified healthcare provider; specialist depends on symptoms and examination.
  1. Step 1

    Check danger signs first

    If danger signs are present, seek emergency care and do not wait for online information.

  2. Step 2

    Record the symptom story

    Write when symptoms started, severity, medicines already taken, allergies, pregnancy status, and test results.

  3. Step 3

    Visit a qualified clinician

    A doctor, nurse, or qualified healthcare provider can examine you and decide which tests or treatment are needed.

  4. Step 4

    Do only useful tests

    Do tests after clinical assessment. Avoid unnecessary tests, random antibiotics, or repeated medicines without diagnosis.

  5. Step 5

    Follow up and return early if worse

    If symptoms worsen, new warning signs appear, or treatment is not helping, return for review quickly.

Rural patient practical tips
  • Take a written symptom diary and all previous prescriptions/test reports.
  • Do not hide medicines already taken, even herbal or over-the-counter medicines.
  • Ask which warning signs mean urgent referral to hospital.

This roadmap is for education. A real diagnosis and treatment plan requires history, examination, and clinical judgment.

RX Patient Help

Ask a health question safely

Write your symptom story. A health professional or site editor can review it before any answer is prepared. This box is not for emergency care.

Emergency first: Severe chest pain, breathing trouble, unconsciousness, stroke signs, severe injury, heavy bleeding, or rapidly worsening symptoms need urgent local medical care now.

Frequently Asked Questions

Is this article a replacement for a doctor?

No. It is educational content only. Patients should consult a qualified clinician for diagnosis and treatment.

When should I seek urgent care?

Seek urgent care for severe symptoms, rapidly worsening condition, breathing difficulty, severe pain, neurological changes, or any emergency warning sign.

Continue exploring

Explore this topic across the RX Medical Library

Open a focused A–Z pathway or continue with closely related indexed articles. These links are educational and do not replace personal medical care.

Search this topic
Diseases A–Z Drugs A–Z Lab Tests A–Z Cancer A–Z
Diseases A–Z

Splenius capitis dystonia is a form of cervical (neck) dystonia in which the involuntary muscle spasms are focused…

More from this topic
  1. Vasodilator Drugs

    Vasodilator drugs relax and widen blood vessels, increasing blood flow. A few examples include ACE inhibitors, ARBs, calcium channel blockers, and nitrates.   DefinitionVasodilators are medicines that dilate...

    June 9, 2025 • Drugs (A - Z)
  2. Methamphetamine Hydrochloride – Uses, Dosage, Side Effects, Interaction

    Methamphetamine Hydrochloride is the hydrochloride salt form of methamphetamine, an amphetamine and sympathomimetic amine with CNS stimulating properties. Methamphetamine hydrochloride acts by facilitating the release of catecholamines, particularly noradrenaline and dopamine, from...

    June 5, 2025 • Drugs (A - Z)
  3. Methamphetamine – Uses, Dosage, Side Effects, Interactions

    Methamphetamine is a member of the class of amphetamines in which the amino group of (S)-amphetamine carries a methyl substituent. It has a role as a neurotoxin, a psychotropic drug,...

    June 5, 2025 • Drugs (A - Z)
  4. Vitamin D3 – Uses, Dosage, Side Effects, Interactions

    DefinitionCholecalciferol is a steroid? hormone produced in the skin when exposed to ultraviolet light or obtained from dietary sources. The active form of cholecalciferol, 1,25-dihydroxycholecalciferol (calcitriol) plays an important role...

    March 10, 2025 • Drugs (A - Z)
  5. Imidazole – Uses, Dosage, Side Effects, Interactions

    DefinitionImidazole is an imidazole tautomer which has the migrating hydrogen at position 1. It is a conjugate base of an imidazolium cation. It is a conjugate acid of an imidazolide. It is...

    October 20, 2023 • Drugs (A - Z)
  6. Carbimazole

    Carbimazole is a member of the class of imidazoles that is methimazole in which the nitrogen-bearing hydrogen is converted into its methoxycarbonyl derivative. A prodrug for methimazole, carbimazole is...

    October 20, 2023 • Drugs (A - Z)
  7. Methylthiouracil – Uses, Dosage, Side Effects, Interactions

    DefinitionA thiourea antithyroid agent that inhibits the synthesis of thyroid? hormone. It is used in the treatment of hyperthyroidism?. Methylthiouracil is an organosulfur compound that is used in...

    October 20, 2023 • Drugs (A - Z)
  8. Propylthiouracil – Uses, Dosage, Side Effects, Interactions

    DefinitionPropylthiouracil is a Thyroid? Hormone Synthesis Inhibitor. The mechanism of action of propylthiouracil is as a Thyroid Hormone Synthesis Inhibitor. 6-propyl-2-thiouracil is a pyrimidine-thione consisting of uracil in which the...

    October 20, 2023 • Drugs (A - Z)
  9. Methimazole

    DefinitionMethimazole ( Metirox 5 and 10 mg) is a member of the class of imidazoles that it imidazole-2-thione in which a methyl group replaces the hydrogen that is attached to...

    October 20, 2023 • Drugs (A - Z)
  10. Mirogabalin – Uses, Dosage, Side Effects, Interactions

    DefinitionMirogabalin has been used in trials studying the treatment of Post-herpetic Neuralgia, Pain? Associated With Fibromyalgia, and Diabetic peripheral neuropathic pain. Mirogabalin is a medication designed...

    August 12, 2023 • Drugs (A - Z)