OXYTETRACYCLINE

Posology Oxytetracycline tablets are for oral administration and and are best taken on an empty stomach (1 hour before food or two hours after), with a glass of water. If gastric irritation occurs, tablets should be taken with food.

Food and some dairy products may interfere with absorption. Tablets should be swallowed when standing or sitting down and do not take immediately before going to bed. Therapy should be continued for up to three days after symptoms have subsided.

All infections due to Group A beta-haemolytic streptococci should be treated for at least 10 days.

Adults (including the elderly) and children over 12 years:

The minimum recommended dosage is 250mg every six hours. Therapeutic levels are attained more rapidly by the administration of 500mg initially, followed by 250mg every six hours. For severe infections, the dosage may be increased to 500mg every six hours.

Children under 12 years:

Contraindicated in this age group.

Elderly:

Usual adult dose. Caution should be observed as subclinical renal insufficiency may lead to drug accumulation.

Renal impairment:

In general, tetracyclines are contraindicated in renal impairment and the dosing recommendations only apply if use of this class of drug is deemed absolutely essential. Total dosage should be decreased by reduction of recommended individual doses and/or by extending time intervals between doses.

Dosage Recommendations in Specific Infections:

Skin infections: 250-500mg daily in single or divided doses should be administered for at least 3 months in the treatment of acne vulgaris and severe rosacea.

Streptococcal infections:

A therapeutic dose of oxytetracycline should be administered for at least 10 days. Brucellosis: 500mg four times daily accompanied by streptomycin. Sexually transmitted diseases: 500mg four times daily for 7 days is recommended in the following infections: uncomplicated gonococcal infections (except anorectal infections in men); uncomplicated urethra;, endocervical or rectal infection caused by Chlamydia trachomatis; non- gonoccocal urethritis caused by Ureaplasma urealyticum.

Very common (≥1/10); common (≥1/100 to <1/10); uncommon (≥1/1,000 to <1/100); rare (≥1/10,000 to <1/1,000); very rare (<1/10,000); Frequency not known (cannot be estimated from the available data).

Blood and lymphatic disorders:

Frequency not known: Haemolytic anaemia, thrombocytopenia, neutropenia, eosinophilia.

Endocrine disorders:

Frequency not known: brown-black microscopic discoloration of thyroid tissue in use over prolonged periods (No abnormalities of thyroid function are known to occur).

Nervous system disorders:

Frequency not known: Bulging fontanelles in infants, benign intracranial hypertension. ) Cardiac disorders: Frequency not known: Pericarditis.

Gastrointestinal disorders:

Rare: oesophagitis, oesophageal ulceration (Reported in patients receiving capsule and tablet forms of drugs in the tetracycline class. ). Pseudomembranous colitis, intestinal overgrowth of resistant organisms (Candida albicans, in particular), may occur and cause glossitis, rectal and vaginal irritation and inflammatory lesions (with candidial overgrowth) in the anogenital regions.

Similarly, resistant staphylococci may cause enterocolitis. Tooth discolouration, pancreatitis.

Hepatobiliary system disorders:

Frequency not known: Hepatotoxicity (hepatitis, jaundice and hepatic failure), fatty liver degeneration.

Skin and subcutaneous tissue disorders:

Uncommon: Exfoliative dermatitis Frequency not known: Macropapular and erythematous rashes, photo- erythema (Patients exposed to direct sunlight or ultraviolet light should be advised to discontinue treatment if any skin reaction occurs).

Tetracycline drugs may cause permanent tooth discoloration (yellow-grey- brown), if administered during tooth development, in the last half of pregnancy and in infancy up to twelve years of age. Enamel hypoplasia has also been reported.

This adverse reaction is more common during long-term use of the drug but has been observed following repeated short-term courses. The anti-anabolic action of tetracyclines may cause an increase in BUN. While this is not a problem in those with normal renal function, in patients with significantly impaired renal function, higher serum levels of oxytetracycline may lead to azotaemia, hyperphosphataemia and acidosis.

Absorption is adversely affected by milk, antacids and aluminium, calcium, iron, magnesium and zinc salts. Tetracyclines depress plasma prothrombin activity, therefore reduced dosages of concurrent anticoagulants may be required. When treating venereal disease, where co-existent syphilis is suspected, proper diagnostic procedures should be utilised.

In all such cases, monthly serological tests should be made for at least four months. The use of antibiotics may occasionally result in the overgrowth of nonsusceptible organisms including Candida. Constant observation of the patients is essential.

If a resistant organism appears, the antibiotic should be discontinued and appropriate therapy instituted. In long-term therapy, periodic laboratory evaluation of organ systems, including haematopoietic, renal and hepatic studies should be performed.

High doses of tetracyclines have been associated with a syndrome involving fatty liver degeneration and pancreatitis. The use of tetracyclines in general is contraindicated in renal impairment due to excessive systemic accumulation and used with caution in patients with hepatic impairment or those receiving drugs which may have hepatotoxic effects; high doses should be avoided.

Known hypersensitivity to any of the tetracyclines or any of the other ingredients in the formulation; chronic renal/hepatic dysfunction; systemic lupus erythematosus; children under 12 years; pregnancy and breastfeeding women; patients receiving vitamin A or retinoid therapy.