Usage
Oxytetracycline is a broad-spectrum antibiotic prescribed for various bacterial infections. These include infections of the respiratory tract, urinary tract, skin, ear, eye, and sexually transmitted infections like gonorrhea. It is also effective against rickettsial infections (like typhus and Rocky Mountain spotted fever), brucellosis, cholera, tularemia, and infections caused by Chlamydia, Mycoplasma, and Rickettsia. It serves as an alternative when penicillin or macrolides cannot be used due to allergies. It is classified as a tetracycline antibiotic.
Pharmacological Classification: Antibiotic
Mechanism of Action: Oxytetracycline inhibits bacterial protein synthesis by binding reversibly to the 30S ribosomal subunit, blocking the attachment of aminoacyl-tRNA to the acceptor site on the mRNA-ribosome complex. This prevents the addition of amino acids to the elongating peptide chain, halting bacterial growth.
Alternate Names
Oxytetracycline Hydrochloride, Terramycin (brand name - no longer available in the US)
How It Works
Pharmacodynamics: Oxytetracycline exerts a bacteriostatic effect by inhibiting bacterial protein synthesis.
Pharmacokinetics:
- Absorption: Incompletely and irregularly absorbed from the gastrointestinal tract, reduced by food, milk, and antacids containing aluminum, calcium, or magnesium.
- Distribution: Widely distributed throughout the body, crossing the placenta and entering breast milk.
- Metabolism: Partially metabolized in the liver.
- Elimination: Primarily excreted in urine and feces, with some biliary excretion.
Mode of Action: Inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit.
Receptor Binding/Enzyme Inhibition/Neurotransmitter Modulation: Binds to the 30S ribosomal subunit.
Elimination Pathways: Renal and fecal excretion, some biliary excretion.
Dosage
Standard Dosage
Adults: 250-500 mg every six hours. Doses up to 1-2 grams divided into four doses may be used for severe infections.
Children: Generally not recommended for children under 8 years old due to the risk of permanent tooth discoloration. For children over 8 years: 25–50 mg/kg/day divided into four equal doses.
Special Cases:
- Elderly Patients: Standard adult dose. Caution is advised due to potential subclinical renal insufficiency.
- Patients with Renal Impairment: Contraindicated unless absolutely necessary. Dosage reduction and/or extended intervals between doses are required if used.
- Patients with Hepatic Dysfunction: Contraindicated in severe liver disease. Caution recommended in mild to moderate impairment.
- Patients with Comorbid Conditions: No explicit dosage adjustments mentioned except for considerations related to renal/hepatic impairment.
Clinical Use Cases
Dosage information for the specific listed clinical settings (Intubation, Surgical Procedures, Mechanical Ventilation, ICU Use, Emergency Situations) is not available from the sources provided. Dosages mentioned relate to specific infections.
Dosage Adjustments
- Renal Impairment: Dosage reduction required.
- Hepatic Dysfunction: Dosage reduction in moderate cases, contraindicated in severe disease.
Side Effects
Common Side Effects
Nausea, vomiting, diarrhea, loss of appetite, upset stomach, photosensitivity, skin rash.
Rare but Serious Side Effects
Anaphylaxis, hepatotoxicity (hepatitis, jaundice, hepatic failure), intracranial hypertension, pancreatitis (high doses), blood disorders (hemolytic anemia, thrombocytopenia, neutropenia, eosinophilia), pericarditis.
Long-Term Effects
Permanent tooth discoloration (yellow-gray-brown) and enamel hypoplasia, especially in children under 8 years of age, pregnant women in their second or third trimester, and with prolonged use.
Adverse Drug Reactions (ADR)
Anaphylaxis, severe skin reactions, hepatotoxicity, blood disorders, intracranial hypertension.
Contraindications
Hypersensitivity to tetracyclines, severe liver/kidney disease, porphyria, systemic lupus erythematosus (SLE), pregnancy (especially second and third trimester), children under 8 years old, concurrent use of vitamin A or retinoids.
Drug Interactions
Antacids (aluminum, calcium, magnesium), iron supplements, bismuth subsalicylate, milk and dairy products, oral contraceptives, anticoagulants (warfarin), digoxin, lithium, methotrexate, retinoids (isotretinoin, acitretin).
Pregnancy and Breastfeeding
Pregnancy Safety Category: Contraindicated, especially during the second and third trimesters, due to risk of permanent tooth discoloration and skeletal development issues in the fetus.
Breastfeeding: Short-term use is generally considered acceptable, though prolonged use should be avoided as a precaution.
Drug Profile Summary
- Mechanism of Action: Inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit.
- Side Effects: Nausea, vomiting, diarrhea, photosensitivity, rash. Serious side effects include anaphylaxis, hepatotoxicity, intracranial hypertension.
- Contraindications: Hypersensitivity to tetracyclines, severe liver/kidney disease, porphyria, SLE, pregnancy, children under 8 years old, concurrent use of vitamin A or retinoids.
- Drug Interactions: Antacids, iron supplements, oral contraceptives, anticoagulants, digoxin, lithium, retinoids.
- Pregnancy & Breastfeeding: Contraindicated in pregnancy. Short-term use acceptable in breastfeeding, avoid prolonged use.
- Dosage: Adults: 250-500 mg every 6 hours. Children over 8 years old: 25-50 mg/kg/day divided into four doses.
- Monitoring Parameters: Renal and liver function tests, complete blood count, signs of hypersensitivity.
Popular Combinations
No specific popular drug combinations are mentioned in the provided sources. However, it is sometimes used in combination with streptomycin for brucellosis.
Precautions
- General Precautions: Assess renal and hepatic function before and during prolonged therapy. Monitor for signs of hypersensitivity. Advise patients to avoid excessive sun exposure.
- Specific Populations: Avoid in pregnancy, caution in breastfeeding. Not recommended for children under 8 years old. Use with caution in the elderly and those with renal impairment.
- Lifestyle Considerations: Alcohol may be consumed in moderation. Smoking does not directly interact with oxytetracycline. Dairy products and antacids should be avoided near the time of dosing. Photosensitivity reactions may occur; sun protection is advised.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Oxytetracycline?
A: Adults: 250-500 mg every six hours. Children over 8 years old: 25-50 mg/kg/day divided into four doses. Adjust dosage in renal impairment. Contraindicated in severe liver disease.
Q2: What are the common side effects of Oxytetracycline?
A: Common side effects include nausea, vomiting, diarrhea, loss of appetite, and photosensitivity.
Q3: What are the serious side effects of oxytetracycline?
A: Serious side effects include anaphylaxis, hepatotoxicity, intracranial hypertension, and blood disorders.
Q4: Who should not take Oxytetracycline?
A: Pregnant women, children under 8, people with severe liver or kidney disease, porphyria, SLE, and those with a hypersensitivity to tetracyclines.
Q5: Can I take antacids with Oxytetracycline?
A: No, antacids can interfere with the absorption of oxytetracycline and should be taken at least 2 hours apart.
Q6: What infections is Oxytetracycline used to treat?
A: Respiratory tract infections, urinary tract infections, skin infections, some sexually transmitted infections (like gonorrhea), rickettsial infections, brucellosis, cholera, and others.
Q7: Can I take Oxytetracycline if I’m allergic to penicillin?
A: Yes, oxytetracycline is often used as an alternative in patients allergic to penicillin.
Q8: How long should I take Oxytetracycline?
A: Continue treatment for at least 24-48 hours after symptoms subside, or as directed by your physician. For streptococcal infections, treatment should continue for at least 10 days.
Q9: Can I take this medication if I am breastfeeding?
A: Limited short-term use is considered acceptable, but prolonged courses are not recommended. Discuss the risks and benefits with your doctor.
Q10: Can I consume dairy products with this medicine?
A: No. Dairy products, including milk, can chelate with oxytetracycline, significantly reducing its absorption. It’s advised to avoid dairy products an hour before and two hours after taking oxytetracycline.
