DOXYCYCLIN

MOA:
  • Doxycycline inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit. 
  • Doxycycline has bacteriostatic activity against a broad range of Gram-positive and Gram-negative bacteria.
USES:
  • Doxycycline is indicated for treatment of
  • Rocky Mountain spotted fever, typhus fever and the typhus group, Q fever, rickettsialpox, and tick fevers caused by Rickettsia
  • Respiratory tract infections caused by Mycoplasma pneumoniae
  • Lymphogranuloma venereum, trachoma, inclusion conjunctivitis, and uncomplicated urethral, endocervical, or rectal infections in adults caused by Chlamydia trachomatis
  • Psittacosis (ornithosis) caused by Chlamydia psittaci
  • Englishman visiting chloroquine and mefloquine resistant malaria 
  • Nongonococcal urethritis caused by Ureaplasma urealyticum
  • Relapsing fever due to Borrelia recurrentis
  • Chancroid caused by Haemophilus ducreyi
  • Plague due to Yersinia pestis
  • Tularemia due to Francisella tularensis
  • Cholera caused by Vibrio cholerae( single dose)
  • Campylobacter fetus infections
  • Brucellosis caused by Brucella species (in conjunction with streptomycin)
  • Bartonellosis caused by Bartonella bacilliformis
  • Granuloma inguinale caused by Calymmatobacterium granulomatis
  • Lyme disease caused by Borrelia burgdorferi
  • inflammatory acne with comedones
  • Maximum propensity for photodermatitis
  • Doxycycline can be used in renal failure without dose adjustment(least Nephrotoxic)
INTERACTION:
Anticoagulant Drugs

  • Because tetracyclines have been shown to depress plasma prothrombin activity, patients who are on anticoagulant therapy may require downward adjustment of their anticoagulant dosage.
Penicillin
  • Since bacteriostatic drugs may interfere with the bactericidal action of penicillin, it is advisable to avoid giving tetracyclines, including DORYX MPC in conjunction with penicillin.
Antacids And Iron Preparations
  • Absorption of tetracyclines including DORYX MPC is impaired by antacids containing aluminum, calcium, or magnesium, bismuth subsalicylate, and iron-containing preparations.
Oral Contraceptives
  • Concurrent use of tetracyclines, including DORYX MPC may render oral contraceptives less effective.
Barbiturates And Anti-Epileptics
  • Barbiturates, carbamazepine, and phenytoin decrease the half-life of doxycycline.
Penthrane
  • The concurrent use of tetracycline and Penthrane® (methoxyflurane) has been reported to result in fatal renal toxicity.
SIDE EFFECT: 
  •  Common side effects of doxycycline include:
  • Diarrhea
  • Itching of the rectum or vagina
  • Sore mouth
Serious Side Effects of Doxycycline
  • Severe headache
  • Blurry vision
  • Rash or hives
  • Trouble breathing or swallowing
  • Sunburn
  • Yellowing of the skin or eyes
  • Dark-colored urine
  • Light-colored bowel movements
  • Loss of appetite
  • Nausea or vomiting
  • Stomach pain
  • Extreme tiredness or weakness
  • Confusion
  • Less frequent urination
Exam Question
  • Doxycycline can be used in renal failure without dose adjustment
  • Doxycycline is least Nephrotoxic
  • Antibiotic treatment of choice for treating cholera in an adult is a single dose of Doxycycline
  • Doxycycline drug of choice for Non-Gonococcal Urethritis
  • Doxycycline is the drug of choice in Mycoplasma infection
  • Doxycycline is the drug of choice in typhus fever
  • Doxycycline is the drug of choice in Brucellosis 
  • Doxycycline acts by inhibiting protein synthesis 
  • Doxycycline has maximum propensity for photodermatitis
  • Chemoprophylaxis in an Englishman visiting chloroquine and mefloquine resistant malaria region is done with Doxycycline
  • A 19-year old male presents with several comedones, papules and pustules on face and trunk. The drug ,1choice for the patient would be Topical retinoic acid + Oral doxycycline

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