Doxycycline is tetracycline derivative with actions similar to that of tetracycline. It is more active than tetracycline against many bacterial species including the enterococci and various anaerobes. Cross-resistance is common although some tetracycline resistant staphylococcus aurus respond to Doxycycline. Doxycycline is reported to be more active against protozoa, particularly plasmodium spp. It may sometimes be preferred to other tetracycline in the treatment of sensitive infections because of its fairly reliable and ling half which permits less frequent dosage.
Route of administration: Oral
Dosage and administration: (Adults) 200mg on the first day, then 100 mg once a day. For acne, take 50mh daily for 6-10weeks. Overdose and treatment. The clinical features of overdose are : Nausea, anorexia, diarrhea, perianal itching, skin eruption, fever, anaphyiaxis and liver damage. Emesis or gastric lavage should be considered in case of overdose. Seek Medical advice immediately.
Contra-Indications: it is contra-indicated in patients with pregnancy and children under 8 years of age should ot be treated with doxycycline as tetracycline may cause permnant discoloration of teeth, enamel hypoplasia and inhibition of linear skeletal growth.
Side effects: Gastro-intestinal effects including nausea, vomiting and diarrhea are common especially with high doses and are most attributed to irritation of the mucosa. Other effects have been reported include dry mouth, glossitis and discoloration of the tongue, stomatitis, and dysphagia. Oesophageal u;ceration has also been reported, particularly after ingestion of capsules or tablets with sufficient water at bedtime. Gastro-intestinal disturbance are reported to be less frequent that with tetracycycline. Doxycycline may also cause less tooth discoloration.
Adverse reaction: the absorption of Doxycyline is reduced by divalent and trivalent cations such as aluminum, bismuth, calcium, iron, magnesium, and Zinc. Therefore, concomitant administration of doxycycline with antacids, iron preparations, some foods such as milk, and diary products or other preparations containing such cations whether active ingredients or excipients, may result in sub therapeutic serum concentrations of the antibacterial agent. The metabolism of doxycycline may be accelerated by drugs that induce hepatic enzymes such as alcohol, antiepileptic including carbamazephine, phenobarbitone, and phenytom and rifampicin.
Teratogenicity: Doxycycline is teratogenic
Warning:care must be taken when liver function is impaired. It is not safe in patient with porphyria.
Storage: should be stord in a cool, and dry place, and away from sunlight and heat.
Keep all medicine out of the reach of children.