Doxycycline is α-6-deoxy-5-oxytetracycline. Doxycycline has high degree of lipid solubility and a low affinity for calcium binding. It is highly stable in normal human serum.
Pharmacology: Microbiology: Doxycycline is primarily bacteriostatic and is thought to exert its antimicrobial effect by inhibition of protein synthesis. Doxycycline is active against a wide range of gram-positive and gram-negative organisms. It is in the tetracycline class having similar antimicrobial spectra. Cross-resistance among tetracyclines is common.
Pharmacokinetics: Tetracyclines are readily absorbed and are bound to plasma proteins in varying degrees. They are concentrated by the liver in bile and excreted in the urine and faeces at high concentrations and in a biologically active form. Doxycycline is virtually completely absorbed after oral administration. Following a 200-mg dose, peak serum levels of 2.6 mcg/mL are reached in 2 hrs in normal adults. Excretion of doxycycline by the kidney is about 40%; serum half-life ranges between 18-22 hrs.
Treatment of infections caused by: Rickettsiae, Haemophilus influenzae, Bacteroides sp, agents of psittacosis and ornithosis, Streptococcus sp, Campylobacter fetus, Venereum and Granuloma inguinale, Staphylococcus aureus, Escherichia coli, Yersinia pestis, Francisella tularensis, Bartonella bacilliformis, Mycoplasma pneumoniae, Klebsiella sp, Vibrio cholerae, agents of lymphogranuloma, Diplococcus pneumoniae, Brucella sp, Haemophilus ducreyi (chancroid), Treponema pallidum, Enterobacter aerogenes, Treponema pertenue and Shigella sp (syphilis and yaws).
200 mg on the 1st day of treatment followed by 100 mg/day up to 48-72 hrs after the patient becomes asymptomatic.
Children Weighing ≤45 kg: 4.4 mg/kg of body weight divided into 2 doses on the 1st day of treatment, followed by 2.2 mg/kg of body weight given as a single daily dose or divided into 2 doses on subsequent days.
In case of overdosage, discontinue Microdox, treat symptomatically and institute supportive measures. Dialysis does not alter serum half-life and thus, would not be of benefit in treating cases of overdosage.
Patients with known hypersensitivity to any of the tetracyclines.
The use of tetracyclines during tooth development (last trimester of pregnancy, infancy and childhood) may cause permanent discoloration of teeth. Photosensitivity manifested by an exaggerated sunburn reaction has been observed in some individuals taking tetracyclines. As with other antibiotics, the use of doxycycline may result in overgrowth of nonsusceptible organisms including fungi.
Use in pregnancy & lactation: Results of animal studies show that tetracyclines cross the placenta and are found in fetal tissues and can have toxic effects on the developing fetus. Hence, the use of doxycycline in pregnancy is not recommended.
Use in children: Microdox is not recommended in children <12 years.
Results of animal studies show that tetracyclines cross the placenta and are found in fetal tissues and can have toxic effects on the developing fetus. Hence, the use of doxycycline in pregnancy is not recommended.
Some of the side effects observed are anorexia, nausea, vomiting, glossitis, erythematous rashes, exfoliative dermatitis and urticaria.
Patients on anticoagulant therapy may require downward adjustment of anticoagulant dosage as tetracyclines depress plasma prothrombin activity. Antacids containing aluminum, calcium and magnesium and iron-containing preparations should not be given to patients taking oral tetracyclines.
Store below 25°C, in a dry place.
J01AA02 - doxycycline ; Belongs to the class of tetracyclines. Used in the systemic treatment of infections.