Tetracycline 250 mg BP
Each capsule contains Tetracycline Hydrochloride BP 250mg
The tetracyclines are mainly bacteriostatic, with a broad spectrum of antimicrobial activity including Chlamydiaceae, Mycoplasma spp., Rickettsia spp., spirochaetes, many aerobic and anaerobic Gram-positive and Gram-negative pathogenic bacteria, and some protozoa.
Mechanism of action
Tetracyclines are taken up into sensitive bacteria cells by an active transport process. Once within the cell they bind reversibly to the 30S subunit of the ribosome, preventing the binding of aminoacyl transfer RNA and inhibiting protein synthesis and hence cell growth. Although tetracyclines also inhibit protein synthesis in mammalian cells they are not actively taken up, permitting selective activity against the infecting organism.
Tetracycline is incompletely absorbed from the gastrointestinal tract, about 60 to 80% of a dose of the drug usually being available. The degree of absorption is diminished by the presence of divalent and trivalent metal ions, with which tetracycline forms stable insoluble complexes, and to a variable degree by milk or food. Administration of tetracycline 500 mg by mouth every 6 hours generally produces steady-state plasma concentrations of 4 to 5 micrograms/mL, peak plasma concentrations occur about 1 to 3 hours after oral use. In the circulation, about 20 to 65% of tetracycline is bound to plasma proteins. It is widely distributed throughout the body tissues and fluids and has an elimination half life of between 6-12 hours. The duration of action is 8 hours and it is excreted in the urine and faeces and also in the bile.
Tetracycline has been used in the treatment of a large number of infections caused by susceptible organisms, with the emergence of bacterial resistance and the development of other antibacterials their use has become more restricted, but it remains the usual drug of choice in rickettsial infections, including ehrlichiosis, Q fever, spotted fevers, and typhus; trench fever; chlamydial infections, including psittacosis, lymphogranuloma venereum, trachoma, non-gonococcal urethritis, chlamydial conjunctivitis, and pharyngitis, sinusitis or pneumonia due to Chlamydia pneumoniae; and mycoplasmal infections, especially pneumonia caused by Mycoplasma pneumoniae.
Tetracycline is contraindicated in patients hypersensitive to any of this group of antibacterials, since cross-sensitivity may occur. They should be avoided in patients with systemic lupus erythematosus. It is considered to be contra-indicated in renal impairment, particularly if severe: if it must be given, doses should be reduced.
The absorption of tetracycline is reduced by divalent and trivalent cations such as aluminum, bismuth, calcium, iron, magnesium and zinc, therefore concomitant administration of tetracycline with antacids, iron preparations, some foods such as milk and dairy products or other preparations containing such cations, whether as active ingredients or excipients may result in subtherapeutic serum concentrations of the antibacterial. Sodium bicarbonate, colestipol and kaolin-pectin are also reported to reduce tetracycline absorption, but potential reduction due to cimetidine or sucralfate are probably of little clinical significance. The nephrotoxic effects of tetracycline may be exacerbated by diuretics, methoxyflurane, or other potentially nephrotoxic drugs. Potentially hepatotoxic drugs should be used with caution in patients receiving tetracycline.
Tetracyclines may decrease the effectiveness of oral contraceptives.
Care should be taken if tetracycline is given to patients with hepatic impairment and high doses should be avoided. Patients who may be exposed to direct sunlight should be warned of the risk of photosensitivity. Care is advisable in patients with myasthenia gravis, who may be at risk of neuromuscular blockade. When given by mouth, tetracycline should be taken with plenty of fluid while sitting or standing, and well before going to bed, to avoid the risk of oesophageal ulceration. Teracycline may interfere with some diagnostic tests including determination of urinary catecholamines or glucose.
PREGNANCY AND LACTATION
Tetracycline should not be used during pregnancy because of the risk of hepatotoxicity in the mother as well as the effects on the developing fetus. It should also be avoided during breast feeding and in children under the age of 8 years. Use in pregnancy, potentially during breast feeding, or in childhood, may result in-impaired bone growth and permanent discoloration of the child’s teeth.
The side-effects of tetracycline are common to all tetracyclines. Gastro-intestinal effects including nausea, vomiting, and diarrhea are common especially with high doses and most are attributed to irritation of the mucosa. Other effects that have been reported include dry mouth, glossitis and discoloration of the tongue, stomatitis, and dysphagia. Oesophageal ulceration has also been reported particularly after ingestion of capsules or tablets with insufficient water at bedtime. Oral candidiasis, vulvovaginitis, and pruritus may occur, mainly due to overgrowth with Candida albicans, and there may be overgrowth of resistant coliform organisms, such as Pseudomonas spp. and Proteus spp., causing diarrhoea.
DOSAGE AND ADMINISTRATION
The usual adult dosage of tetracycline hydrochloride is 250 or 500mg every 6 hours by mouth, preferably one hour before or 2 hours after meals.
Children over 8 years in doses of 25 to 50 mg/kg daily in divided doses.
Care is required if tetracycline is given to the elderly. It should be avoided if possible in renal impairment and doses reduced if they must be used.
The dosage of Tetracycline should not exceed 1g daily in patients with known liver disease.
Overdosage symptoms may include nausea, vomiting and diarrhea. There is no specific antidote for Tetracycline overdose, management of the patient should consist of symptomatic and supportive therapy.
Blisters of 10 x 10 capsules
Store in a cool and dry place below 30oC. Protect from light.
Keep all medicines out of reach of children.
YANGZHOU NO. 3 PHARMACEUTICAL CO., LTD.
No. 51 Guotai Road, Yiling Town, Jiangdu City, Jiangsu, China.
Geneith PHARM. LIMITED
12, Adewale Crescent,
Off Ewenla Street
Off Oshodi-Apapa Exp. Way
NAFDAC REQ. NO.: 04-3466