Tetracycline, Uses, Dosage, Side effects, Interactions, Pregnancy

Last updated: February 7, 2026Reviewed date: February 7, 2026Reading time: 10 min read
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Tetracycline is a broad-spectrum naphthacene antibiotic produced semisynthetically from chlortetracycline, an antibiotic isolated from the bacterium Streptomyces aureofaciens. In bacteria, tetracycline binds to the 30S ribosomal subunit, interferes with the binding of aminoacyl-tRNA to the mRNA-ribosome complex, thereby inhibiting protein synthesis. Tetracycline is a broad spectrum polyketide antibiotic produced by the...

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

Tetracycline is a broad-spectrum naphthacene antibiotic produced semisynthetically from chlortetracycline, an antibiotic isolated from the bacterium Streptomyces aureofaciens. In bacteria, tetracycline binds to the 30S ribosomal subunit, interferes with the binding of aminoacyl-tRNA to the mRNA-ribosome complex, thereby inhibiting protein synthesis. Tetracycline is a broad spectrum polyketide antibiotic produced by the Streptomyces genus of Actinobacteria. It exerts a bacteriostatic effect on bacteria by binding reversible to the bacterial 30S ribosomal subunit...

Key Takeaways

  • This article explains Machanism of Action of Tetracycline in simple medical language.
  • This article explains Indications of Tetracycline in simple medical language.
  • This article explains Contra Indications of Tetracycline in simple medical language.
  • This article explains Dosage of Tetracycline  in simple medical language.
Educational health guideWritten for patient understanding and clinical awareness.
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Emergency safety firstUrgent warning signs are highlighted below.

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.

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Learn safely

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

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Definition

Tetracycline is a broad-spectrum naphthacene 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 produced semisynthetically from chlortetracycline, an antibiotic isolated from the bacterium Streptomyces aureofaciens. In bacteria, tetracycline binds to the 30S ribosomal subunit, interferes with the binding of aminoacyl-tRNA to the mRNA-ribosome complex, thereby inhibiting protein synthesis.

Tetracycline is a broad spectrum polyketide 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 produced by the Streptomyces genus of Actinobacteria. It exerts a bacteriostatic effect on bacteria by binding reversible to the bacterial 30S ribosomal subunit and blocking incoming aminoacyl tRNA from binding to the ribosome acceptor site.

Machanism of Action of Tetracycline

Tetracycline passively diffuses through porin channels in the bacterial membrane and reversibly binds to the 30S ribosomal subunit, preventing binding of tRNA to the mRNA-ribosome complex, and thus interfering with protein synthesis.

Tetracycline is a short-acting 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 that inhibits bacterial growth by inhibiting translation. It binds to the 30S ribosomal subunit and prevents the amino-acyl tRNA from binding to the A site of the ribosome. It also binds to some extent to the 50S ribosomal subunit. This binding is reversible in nature. Additionally tetracycline may alter the cytoplasmic membrane of bacteria causing leakage of intracellular contents, such as nucleotides, from the cell.

The hepatotoxic effects of tetracycline (I), rolitetracycline, and doxycycline were studied in male and female mice. All antibiotics (25-100 ug/g) increased the amount of unconjugated and total jaundice. সহজ বাংলা: জন্ডিসে বাড়তে পারে এমন হলুদ রঞ্জক।" data-rx-term="bilirubin" data-rx-definition="Bilirubin is a yellow pigment that can build up in jaundice. সহজ বাংলা: জন্ডিসে বাড়তে পারে এমন হলুদ রঞ্জক।">bilirubin. This effect was most pronounced after tetracycline, which also reduced the level of conjugated bilirubin. All drugs increased serum transaminase enzyme levels; this effect was more pronounced in females.

Indications of Tetracycline

  • Bacterial Infection
  • Bladder Infection
  • Acne
  • Bronchitis
  • Brucellosis
  • Bullous Pemphigoid
  • Chlamydia Infection
  • Ehrlichiosis
  • Epididymitis, Sexually Transmitted
  • Gonococcal Infection, Uncomplicated
  • Helicobacter Pylori Infection
  • Lyme Disease, pain, swelling, stiffness, or reduced movement. সহজ বাংলা: জয়েন্টের প্রদাহ।" data-rx-term="arthritis" data-rx-definition="Arthritis means joint inflammation causing pain, swelling, stiffness, or reduced movement. সহজ বাংলা: জয়েন্টের প্রদাহ।">Arthritis
  • Lyme Disease, allergy, infection, or inflammation. সহজ বাংলা: চামড়া লাল হয়ে যাওয়া।" data-rx-term="erythema" data-rx-definition="Erythema means skin redness, often from irritation, allergy, infection, or inflammation. সহজ বাংলা: চামড়া লাল হয়ে যাওয়া।">Erythema Chronicum Migrans
  • Lyme Disease, Neurologic
  • Lymphogranuloma Venereum
  • Nongonococcal Urethritis
  • Ocular Rosacea
  • Ornithosis
  • Pelvic Inflammatory Disease
  • Pemphigoid
  • Pemphigus
  • Pneumonia
  • Psittacosis
  • Rheumatoid Arthritis
  • Rickettsial Infection
  • Syphilis, Early
  • Syphilis, Latent
  • Tertiary Syphilis
  • Upper Respiratory Tract Infection

Used to treat bacterial infections such as Rocky Mountain spotted fever, typhus fever, tick fevers, Q fever, rickettsialpox and Brill-Zinsser disease. May be used to treat infections caused by Chlamydiae spp., B. burgdorferi (Lyme disease), and upper respiratory infections caused by typical (S. pneumoniae, H. influenzae, and M. catarrhalis) and atypical organisms (C. pneumoniae, M. pneumoniae, L. pneumophila). May also be used to treat acne. Tetracycline may be an alternative drug for people who are allergic to penicillin.

Therapeutic Indications of Tetracycline

  • Tetracycline hydrochloride ointment is used in the prophylaxis of minor bacterial skin infections and in the treatment of dermal ulcer.
  • Tetracycline hydrochloride ointment is indicated in the topical treatment of minor skin infections caused by streptococci, staphylococci, and other susceptible organisms.
  • Tetracycline hydrochloride for topical solution is indicated for the topical treatment of acne vulgaris. It may be effective in grades II and III acne, which are characterized by inflammatory lesions such as papules and pustules.
  • Ophthalmic tetracycline is used in the treatment of chlamydia infections and ocular rosacea.
  • Ophthalmic tetracycline is used in the treatment of bacterial blepharitis, blepharoconjunctivitis, bacterial conjunctivitis, bacterial keratitis, bacterial keratoconjunctivitis, and meibomianitis.
  • Ophthalmic tetracycline is indicated in the treatment of trachoma caused by Chlamydia trachomatis. It should be used concurrently with oral tetracyclines.
  • Ophthalmic tetracycline is indicated in the prophylaxis of ophthalmia neonatorum caused by Neisseria gonorrhoea and Chlamydia trachomatis.
  • phthalmic tetracycline is indicated in the treatment of superficial ocular infections caused by Staphylococcus aureus, streptococci including Streptococcus epidermicus (Streptococcus pyogenes) and Staphylococcus pneumonia (Diplococcus pneumonia), Neisseria gonorrhoea, and Escherichia coli.
  • The intrapleural administration of tetracycline solution as a sclerosing agent for the treatment of recurrent malignant pleural effusions is discussed. The usual dose is 500 mg tetracycline hydrochloride diluted in 30-50 ml saline, instilled via a chest tube into the pleural space. Side effects have not been a problem. Considering the effective control rate, toxicity, availability and ease of administration, intrapleural tetracycline appears safe and effective and is considered the first choice for local therapy.
  • Standardized enamel and dentin specimens were impregnated in aqueous solutions of tetracycline HCl, oxytetracycline HCl or doxycyline HCl, rinsed in water, and stored dry for 200 days. Another series of specimens were impregnated in solutions of doxycyline HCl and then rinsed in tap water for varying periods up to 35 days.

Contra Indications of Tetracycline

  • History of severe hypersensitivity (e.g. anaphylactic reaction) to any other type of betalactam antibacterial agent (penicillins, monobactams and carbapenems).
  • Hemolytic anemia
  • Liver problems
  • Interstitial nephritis
  • Subacute cutaneous lupus erythematosus
  • Systemic lupus erythematosus
  • Tetracycline use should be avoided in pregnant or lactating women, and in children with developing teeth because they may result in permanent staining (dark yellow-gray teeth with a darker horizontal band that goes across the top and bottom rows of teeth), and possibly affect the growth of teeth and bones.
  • Usage during the first 12 weeks of pregnancy does not appear to increase the risk of any major birth defects. There may be a small increased risk for minor birth defects such as an inguinal hernia, but the number of reports is too small to be sure if there actually is any risk.

Dosage of Tetracycline 

Acne

  • 500 mg orally twice a day for 2 weeks or more, depending on the nature and severity of the infection

Bronchitis

  • 500 mg orally every 6 hours for 7 to 10 days, depending on the nature and severity of the infection; may be given for 4 to 5 days a week during winter months as prophylaxis against chronic infectious bronchitis

Brucellosis

  • 500 mg orally 4 times a day for 3 weeks given with streptomycin 1 g IM twice a day the first week and once a day the second week

Chlamydia Infection

  • Uncomplicated urethral, endocervical, or rectal infection: 500 mg orally 4 times a day for at least 7 days
  • The patient’s sexual partner(s) should also be evaluated/treated.
  • Oral doxycycline therapy is preferred by the Centers for Disease Control and Prevention (CDC) for the treatment of chlamydial infections in nonpregnant patients.

Helicobacter pylori Infection

  • 500 mg orally every 6 hours for 14 days given in conjunction with bismuth, metronidazole, and an H2 blocker

Lyme Disease Arthritis

  • 500 mg orally every 6 hours for 14 to 30 days, depending on the nature and severity of the infection

Lyme Disease Carditis

  • 500 mg orally every 6 hours for 14 to 30 days, depending on the nature and severity of the infection

Lyme Disease  Erythema Chronicum Migrans

  • 500 mg orally every 6 hours for 10 to 30 days, depending on the nature and severity of the infection

Pneumonia

  • 500 mg orally every 6 hours for 10 to 21 days, depending on the nature and severity of the infection

Upper Respiratory Tract Infection

  • 500 mg orally every 6 hours for 7 to 10 days, depending on the nature and severity of the infection

Psittacosis

  • 500 mg orally 4 times a day; initial treatment with IV doxycycline may be necessary for seriously ill patients
  • Duration: Treatment should continue at least 10 to 14 days after fever subsides to prevent relapse

Nongonococcal Urethritis

  • 500 mg orally every 6 hours for 7 days

Gonococcal Infection

  • 500 mg orally 4 times a day for 7 days

Cystitis

  • 500 mg orally every 6 hours for 3 to 7 days, depending on the nature and severity of the infection; recommended if no alternatives exist

Side Effects of Tetracycline 

The most common side effects 

More common

Rare

Drug Interactions of Tetracycline

Tetracycline may interact with following drugs, suppliments, & may change the efficacy of drugs

Pregnancy & Lactation of Tetracycline 

FDA Pregnancy Category D 

Pregnancy

Tetracycline is classified pregnancy category D. All tetracyclines have a detrimental effect on the skeletal development and bone growth of the fetus or child. They should not be used in the second half of pregnancy unless benefits from treatment outweigh the risks to the fetus, and their use should be considered only with extreme caution.

Lactation

Tetracyclines also have a serious effect on the dentin and enamel of developing teeth, causing permanent yellow or brown discoloration and enamel hypoplasia. Except when other therapy is ineffective, use in neonates, infants, and children to the age of 8 years, should be avoided.Tetracyclines are distributed in small amounts into breast milk. In general, manufacturers recommend that tetracycline antibiotics not be used in breast feeding mothers due to a theoretical risk of causing teeth discoloration, enamel hypoplasia,

References

Doctor visit helper

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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: Tetracycline, Uses, Dosage, Side effects, Interactions, Pregnancy

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.

References

Add references, clinical guidelines, textbooks, journal articles, or trusted medical sources here. You can edit this area from the RX Article Professional Blocks panel.

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