Brand Name : DOXYLENE
Generic Name : Doxycycline
Preparation : 100 mg Capsule
Pharmacological Category : Antibacterial

Mechanism of Action (MOA)
DOXYLENE (Doxycycline) has bacteriostatic activity. DOXYLENE inhibits bacterial protein syntheses by binding to the 30S ribosomal subunit of bacteria.

Pharmacokinetics

  • Absorption : Readily and almost completely absorbed from the gastrointestinal tract
  • Peak Serum Time : 1.5 to 4 hours
  • Bioavailability : Reduced at high pH
  • Distribution : Widely distributed into body tissues and fluids
  • Protein Binding : 80 to 95%
  • Metabolism : Liver
  • Elimination Half-life : 12 to 15 hours
  • Excretion : Urine (23%), faeces (30%)

    • Note : Unlike tetracycline, absorption of doxycycline is not significantly affected by the presence of milk or food in the stomach or duodenum.

Indications and Dosage

  • Susceptible infections : The usual adult dose is two capsules of DOXYLENE on the first day (as a single dose or in divided doses), followed by one capsule of DOXYLENE. In severe infections, the initial dosage is maintained throughout the course of treatment.
  • Uncomplicated Gonococcal Infection : One capsule of DOXYLENE twice daily for 7 days
  • Low Severe Community-acquired Pneumonia : Two capsule of DOXYLENE loading dose, followed by one capsule of DOXYLENE once daily
  • Acute Bacterial Rhinosinusitis : Two capsules of DOXYLENE daily or in two divided dose for 5 days to 7 days
  • Mild to Moderately Severe Pelvic Inflammatory Disease : One capsule of DOXYLENE twice daily for 14 days
  • Acne : Two capsules of DOXYLENE on the first day (as a single dose or in divided doses), followed by one capsule of DOXYLENE daily
  • Periodontal Infection : One to two capsules of DOXYLENE daily
  • Relapsing Fever and Louse-born Typhus : One to two capsules of DOXYLENE as a single dose
  • Prophylaxis of Scrub Typhus : Two capsules of DOXYLENE as a single dose
  • Syphilis in Penicillin-Allergic Patients: One to two capsules of DOXYLENE twice daily for at least 14 days
  • Syphilis more than a year : One capsule of DOXYLENE twice daily for 28 days
  • Ophthalmic Infections : Two capsules of DOXYLENE in 2 divided dose on day 1, followed by one capsule of DOXYLENE once daily
  • Lymphogranuloma Venereum : One capsule of DOXYLENE twice daily for 21 days
  • Skin or Soft Tissue Infections : One capsule of DOXYLENE twice daily
  • Chloroquine-resistant Falciparum Malaria : Two capsules of DOXYLENE for at least 7 days after treatment with quinine.
  • Anthrax Prophylaxis : One capsule of DOXYLENE for 60 days after initial exposure
  • Plague :
    Prophylaxis : Two capsules of DOXYLENE on the first day (as a single dose or in divided doses), followed by one capsule of DOXYLENE daily for next 6 days
    Treatment : Two capsules of DOXYLENE on the first day (as a single dose or in divided doses), followed by one capsule of DOXYLENE daily for the following 9 days

Side Effects
COMMON : Nausea, vomiting, diarrhoea, eosophageal ulceration, glossitis, stomatitis, dysphagia
RARE : Hepatotoxicity

Contraindications
Hypersensitivity to doxycycline, tetracycline, lactation

Warnings / Precautions

  • Oesophageal ulceration may be a particular problem if capsules are taken with insufficient fluid or in a recumbent posture so doxycycline should be taken with at least half a glass of water, in an upright position, and well before going to bed.
  • Doxycycline does not appear to accumulate in patients with impaired renal function. So, aggravation of impairment may be less likely.

Drug Interactions

  • Aluminium, magnesium, calcium containing antacids, milk, or food containing calcium interferes with doxycycline absorption but to a lesser extent than tetracycline.
  • Doxycycline decreases effects of amoxicillin because of antagonistic effect.
  • Ferrous fumarate decreases level of doxycycline by inhibition of gastrointestional absorption.
  • Doxycycline enhances the anticoagulant effect of warfarin (coumadin) because of synergistic effect.
  • Doxycycline increases the level or effect of digoxin by altering intestinal flora.
  • The metabolism of doxycycline may be increased by hepatic enzyme inducers such as rifampicin, phenytoin and carbamazepine, phenobarbital and primidone.
  • Doxycycline may diminish the therapeutic effect of typhoid vaccine, oral contraceptives etc.

Pregnancy Category : D

Presentation
DOXYLENE 100 mg : A box of 10 blisters, each blister of 10 capsules