TETRACYCLINE

Posology Tetracycline Capsules should be swallowed whole with a glass of water one hour before or two hours after a meal since food and some dairy products interfere with absorption. 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 and children over 12 years:

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

Dosage recommendations in specific infections:

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

Streptococcal infections:

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

Acute epididymo-orchitis caused by Chlamydia trachomatis, or Neisseria gonorrhoea, 500 mg four times daily for 10 days. Primary and secondary syphilis: 500 mg four times daily for 15 days. Syphilis of more than one year's duration, (latent syphilis of uncertain or more than one year's duration, cardiovascular or late benign syphilis) except neurosyphilis, should be treated with 500 mg, four times daily for 30 days.

Patient compliance with this regimen may be difficult so care should be taken to encourage optimal compliance. Close follow-up including laboratory tests, is recommended.

Children under 12 years:

Contraindicated for children of this age group.

The following convention has been utilised for the classification of frequency. Very common (≥ 1/10); Common (≥ 1/100 and < 1/10); Uncommon (≥ 1/1000 and < 1/100); Rare (≥ 1/10,000 and < 1/1000); Very rare (< 1/10,000); Frequency not known (cannot be estimated from the available data).

4) Blood and lymphatic system disorders: Rare: haemolytic anaemia, thrombocytopenia, neutropenia, eosinophilia, agranulocytosis, aplastic anaemia. 8), fixed drug eruptions, exfoliative dermatitis.

Endocrine disorders:

Frequency not known: brown-black microscopic discolouration of thyroid tissue. No abnormalities of thyroid function are known to occur.

Nervous system disorders:

Frequency not known: headache.

Eye disorders:

Frequency not known: visual disturbances, permanent visual loss. 3). Presenting features were headache, dizziness, tinnitus and visual disturbances including blurring of vision, scotomata and diplopia. Permanent visual loss has been reported.

Treatment should cease if evidence of raised intracranial pressure develops.

Gastrointestinal disorders:

Rare: dysphagia, oesophagitis and oesophageal ulceration (most of these patients took medication immediately before going to bed or with inadequate fluids). 6). Tooth discolouration has also been seen in adults. If gastric irritation occurs, tablets should be taken with food.

Hepatobiliary disorders:

Rare: transient increases in liver function tests, hepatitis, jaundice, hepatic failure Frequency not known: hepatotoxicity associated with fatty liver.

8). Enamel hypoplasia has been reported. This adverse reaction is more common during long-term use of the drug but has been observed following repeated short-term courses. Photosensitivity reactions may occur in hypersensitive persons and such patients should be warned to avoid direct exposure to natural or artificial sunlight and to discontinue therapy at the first sign of skin discomfort.

Care is advised when administered to patients with myasthenia gravis as weak neuromuscular blockade may occur. Exacerbation of SLE (systemic lupus erythematosus) may occur with the use of tetracyclines. Tetracyclines depress plasma prothrombin activity; therefore reduced dosages of concurrent anticoagulants may be required.

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 tetracycline may lead to azotaemia, hyperphosphataemia and acidosis.

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. 8). Constant observation of the patients is essential.

If a resistant organism appears, the antibiotic should be discontinued and appropriate therapy instituted. Increased intra-cranial pressure, with bulging of the fontanelles has occasionally occurred in infants. This condition rapidly disappears when the drug is withdrawn.

Diarrhoea, particularly if severe, persistent and/or bloody, during or after treatment (including several weeks after treatment) with Tetracycline tablets, may be symptomatic of Clostridium difficile- associated disease (CDAD). 8). It is therefore important to consider this diagnosis in patients who develop serious diarrhoea during or after treatment with Tetracycline tablets.

8).