Doxin

Each capsule contains Doxycycline (as hyclate) equivalent to doxycycline 100 mg.

Pharmacology: Mechanism of Action: Doxycycline is primarily bacteriostatic but is also described as " bactericidal" in low concentrations against some bacterial species eg, Streptococcus pyogenes and Streptococcus pneumoniae.
Doxycycline inhibits bacterial protein synthesis. It binds principally to the 30s subunits of bacterial ribosomes and specifically inhibits the enzyme binding of aminoacyl-t-RNA to the adjacent ribosomal acceptor site.
Doxycycline also inhibits mammalian protein synthesis in higher concentrations.
Spectrum of Activity: Doxycycline exhibits in vitro activity against a wide range of gram-positive and gram-negative organisms. Cross resistance of these organisms to tetracyclines is uncommon.
Because many strains of groups of gram-positive and gram-negative microorganisms have been shown to be resistant to tetracycline, culture and susceptibility testing are recommended. Up to 44% of strains of Streptococcus pyogenes and 74% of Streptococcus faecalis have been found to be resistant to tetracycline drugs. Therefore, tetracycline should not be used for streptococcal disease unless the organism has been demonstrated to be susceptible.
Doxycycline has been found to be active against the asexual erythrocytic forms of Plasmodium falciparum but not against the gametocytes of Plasmodium falciparum.
Clinical Pharmacology: Doxycycline is completely absorbed (90 to 100%) after oral administration. Following a single 100 mg dose in fasting adults with normal renal function, peak serum concentrations are attained within 1.5 to 4 hours and average 1.5 to 2.1 μg/mL. A 200 mg dose produces peak serum concentrations of 2.6 to 3 μg/mL.
Doxycycline is highly lipid soluble and readily penetrates into the cerebrospinal fluid, brain, eye and prostate.
Doxycycline's serum half-life is 14 to17 hours after a single dose and 22 to 24 hours after multiple doses in patients with normal renal function. In patients with severe renal impairment, serum half-life is 18 to 26 hours after a single dose and 20 to 30 hours after multiple doses. Serum half-life of doxycycline is not altered in patients undergoing hemodialysis.
Doxycycline is excreted largely by nonrenal routes. Approximately 20 to 26% of a single oral or IV doxycycline dose is excreted in urine and 20 to 40% is excreted in feces within 48 hours as active drug in patients with normal renal function. In patients with creatinine clearances less than 10 mL/minute, the fraction of doxycycline excreted in urine within 72 hours may decrease to about 1 to 5%. Recent studies show that doxycycline is not metabolized in the liver but is partially deactivated in the intestine by chelate formation.
Spectrum of Activity: Doxycycline exhibits in vitro activity against a wide range of gram-positive and gram-negative organisms. Cross-resistance of these organisms to tetracyclines is uncommon.
Because many strains of groups of gram-positive and gram-negative microorganisms have been shown to be resistant to tetracycline, culture and susceptibility testing are recommended. Up to 44% of strains of Streptococcus pyogenes and 74% of Streptococcus faecalis have been found to be resistant to tetracycline drugs. Therefore, tetracycline should not be used for streptococcal disease unless the organism has been demonstrated to be susceptible.
Doxycycline has been found to be active against the asexual erythrocytic forms of Plasmodium falcifarum but not against the gametocytes of Plasmodium falciparum.

Treatment of infections caused by susceptible strains of the following microorganisms in the conditions listed below:
Sexually transmitted diseases due to Chlamydia trachomatis, Ureaplasma urealyticum, Haemophilus ducreyi and Calymmatobacterium granulomatis; Urinary tract infections due to Enterobacter aerogenes, Klebsiella spp and Acinetobacter spp; respiratory tract infections caused by Mycoplasma pneumoniae, Haemophilus influenzae, Streptococcus pneumoniae and Klebsiella spp; gastrointestinal infections due to Vibrio cholerae and Shigella spp; systemic infections caused by Rickettsiae, Borrelia recurrentis, Yersinia pestis, Francisella tularensis, Bartonella baciliformis and Brucella spp; infections caused by Escherichia coli, Enterobacter aerogenes, Shigella spp and Acinetobacter spp.
When penicillin is contraindicated, doxycycline is an alternative drug in the treatment of the following infections: Uncomplicated gonorrhea caused by Neisseria gonorrhoeae, syphilis caused by Treponema pallidum, yaws caused by Treponema pertenue, listeriosis due to Listeria monocytogenes, anthrax due to Bacillus anthracis, Vincent's infection caused by Fusobacterium fusiforme, actinomycosis caused by Actinomyces israelii, infections caused by Clostridium spp.
In acute intestinal amebiasis, doxycycline may be a useful adjunct to amebicides.
In severe acne, doxycycline may be a useful adjunctive therapy.
In refractory periodontitis and periodontal abscess, doxycycline may be a useful adjunctive therapy.
Prophylaxis: Prophylaxis of malaria due to Plasmodium falciparum in short-term travelers (<4 months) to areas with Chloroquine and/or pyrimethamine-sulfadoxine resistant strains.

Adult: Orally, 200 mg on the first day of treatment (100 mg every 12 hours) followed by a maintenance dose of 100 mg/day once daily preferably with meals to reduce gastric irritation.
Management of more severe infections (particularly chronic infections of the urinary tract): 100 mg every 12 hours is recommended. Or as prescribed by a physician. See table.

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Hypersensitivity to any of the tetracyclines.

Pregnancy: Category D. do not use tetracycline during pregnancy. Tetracyclines readily cross the placenta, are found in fetal tissues and can have toxic effects on the developing fetus (retardation of skeletal development). Evidence of embryotoxicity has also been noted in animals treated early in pregnancy.
Lactation: Tetracyclines are excreted in breast milk. A dosage of 2 g/day for 3 days has achieved a milk plasma ratio of 0.6 to 0.8.
Because of potential adverse reactions, decide whether to discontinue nursing or the drug, taking into account the importance of the drug to the mother.
Pediatric Use: Do not use in children aged 8 years and below because of the effect of tetracyclines in teeth (permanent discoloration and possibly enamel hypoplasia) and bone.

Benign intracranial hypertension manifested as headache and blurred vision has been reported in adults receiving tetracyclines. Bulging fontanels have been associated with tetracycline use in infants. While both conditions and related symptoms usually resolve on tetracycline discontinuation, possibility for permanent sequelae exists.
As with other antibiotic preparations, use of doxycycline may result in overgrowth of nonsusceptible organisms, including fungi. Discontinue antibiotic if superinfection occurs and institute appropriate therapy.
Laboratory tests: In venereal disease, when co-existent syphilis is suspected, perform dark field examinations before treatment is started and repeat blood serology monthly for at least 4 months.
Perform laboratory evaluation of organ systems, including hematopoietic, renal and hepatic studies in long-term therapy.
Expired products: Do not administer expired tetracyclines under any circumstance. Its degradation products are highly nephrotoxic and have on occasion, produced a Fanconi-like syndrome.

Due to oral Doxycycline's virtually complete absorption, side effects of the lower bowel, particularly diarrhea, have been infrequent.
The following reactions have been observed with tetracyclines: Gastrointestinal: Anorexia, nausea, vomiting, diarrhea, glossitis, dysphagia, enterocolitis and inflammatory lesions (with monilial overgrowth) in the anogenital region. Rarely, hepatotoxicity, esophagitis and esophageal ulcerations.
Skin: Maculopapular and erythematous rashes; exfoliative dermatitis (uncommon).
Renal: Rise in BUN (dose-related).
Hypersensitivity reactions: Urticaria, angioneurotic edema, anaphylaxis, anaphylactoid purpura, serum sickness, pericarditis and exacerbation of systemic lupus erythematosus.
Blood: Hemolytic anemia, thrombocytopenia, neutropenia and eosinophilia.
Others: Bulging fontanels in infants and intracranial hypertension in adults.
when given over prolonged periods, tetracyclines have been reported to produce brown-black microscopic discoloration of the thyroid gland. No abnormalities of thyroid function studies are known to occur.

Because tetracyclines depress plasma prothrombin activity, patients who are on anticoagulant therapy may require reduction of their anticoagulant dosage.
Since bacteriostatic drugs interfere with the bactericidal action of penicillin, it is advisable to avoid giving tetracyclines in conjunction with penicillin.
Absorption of tetracyclines is impaired by bismuth subsalicylate and antacids containing aluminum, calcium, or magnesium and iron-containing preparations.
Barbiturates, carbamazepine and phenytoin decrease the half-life of doxycycline.
Concurrent use of tetracycline and methoxyflurane has been reported to result in fatal renal toxicity. Concurrent use of tetracycline may render oral contraceptives less effective.

Store at temperatures not exceeding 30°C.

Patient Information: Drink plenty of fluids along with doxycycline to reduce risk of esophageal irritation and ulceration.
Food, especially those which contain calcium, reduces absorption of tetracycline. However, doxycyline's absorption is not markedly influenced by simultaneous ingestion of food or milk.
Avoid excessive sunlight or artificial ultraviolet light while taking doxycycline. Discontinue therapy if phototoxicity occurs.
Chronic doxycycline use increases incidence of vaginal candidiasis.

Tetracyclines

J01AA02 - doxycycline ; Belongs to the class of tetracyclines. Used in the systemic treatment of infections.

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