Doxycycline

Doxycycline is a broad-spectrum tetracycline antibiotic effective against gram-positive and gram-negative bacteria, spirochetes, mycoplasma, rickettsia and mycobacteria. It is used as an alternative to penicillin in gonorrhea and syphilis. Doxycycline is indicated for respiratory tract infections, gastrointestinal infections, chlamydial infections, sexually transmitted diseases, skin infections, brucellosis, tularemia, cellulitis, acne, Q-fever, malaria prophylaxis and anthrax post-exposure prophylaxis. It should be taken on an empty stomach and dairy products should be avoided. Complete the full course of treatment even if symptoms improve.

• Respiratory tract infections (pneumonia, influenza, sinusitis, bronchitis, tonsillitis, tracheitis)
• Gastrointestinal tract infections (cholera, traveler's diarrhea, shigella dysentery, acute intestinal amebiasis)
• Chlamydial infections (lympho-granuloma venereum, psittacosis, trachoma)
• Sexually transmitted diseases (non-gonococcal urethritis, acute pelvic inflammatory disease, urethral and endocervical infections, gonorrhoea, syphilis, pyelonephritis, cystitis)
• Other infections (impetigo, furunculosis, inclusion conjunctivitis, brucellosis, tularemia, cellulitis, acne, Q-fever)
• Malaria prophylaxis (short-term travelers)
• Anthrax (post-exposure prophylaxis)
• Rickettsial infections (Rocky Mountain spotted fever, typhus fever, Q fever)

Doxycycline is a semisynthetic tetracycline antibiotic with broad spectrum activity. It is primarily a bacteriostatic antibiotic. Doxycycline binds to the 30S ribosomal subunit and inhibits bacterial protein synthesis. It is particularly active against Staphylococcus aureus and Nocardia. It is active against penicillin-resistant strains of Staphylococcus aureus and strains resistant to other tetracyclines.

Doxycycline inhibits bacterial protein synthesis by binding to the 30S ribosomal subunit. It has bacteriostatic activity against a broad range of gram-positive and gram-negative bacteria.

Adult Dose:

• Susceptible infections: 200 mg on day 1 as single or divided doses, then 100 mg once daily for 7-10 days.
• Severe infections: Maintain initial dose throughout treatment.
• STDs (Chlamydia/non-gonococcal urethritis): 100 mg q12hr for 7 days; Syphilis (early): 100 mg BID x 2 weeks; Syphilis (>1 year): 100 mg BID x 4 weeks.
• Acne/Rosacea: 50 mg daily for 6-12 weeks.
• Malaria prophylaxis: 100 mg daily; start 1-2 days before travel and continue for 4 weeks after.
• Cholera: 300 mg single dose.
• Anthrax (post-exposure): 100 mg BID for 60 days.

Child Dose (>8 years, <45 kg): 2-4 mg/kg/day divided q12h.

Oral tablet or capsule. Take in the dose and duration as advised by your doctor. Swallow whole. Do not chew, crush or break. Take on an empty stomach (1 hour before or 2 hours after meals). Avoid dairy products. Take while sitting or standing with plenty of fluid and do not lie down for at least 30 minutes after taking.

If you miss a dose of Doxycycline, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular schedule. Do not double the dose.

Common Side Effects:

• Vomiting
• Nausea
• Diarrhea
• Abdominal pain
• Skin rash

Other Side Effects:

• Hemolytic anemia
• Eosinophilia
• Blurred vision
• Dizziness
• Drowsiness

• Doxycycline cures infection and improves symptoms.
• Take with food and plenty of water to avoid stomach upset.
• Complete the full course of treatment even if you feel better. Stopping early may cause infection to return.
• Take while sitting or standing to prevent throat irritation and do not lie down for 30 minutes.
• Diarrhea may occur as a side effect; inform doctor if it persists or if blood in stools.
• Avoid excessive sun exposure; use sunscreen and protective clothing.
• May cause blurred vision or drowsiness; do not drive if these symptoms occur.
• Do not use in children under 8 years due to risk of permanent tooth discoloration.

• Hypersensitivity to tetracyclines
• Severe hepatic disorder
• Systemic lupus erythematosus
• Pregnancy (risk to fetal bone growth and tooth staining)
• Lactation (drug enters breast milk)
• Children under 8 years (permanent tooth discoloration)

Concomitant use with isotretinoin may cause pseudotumour cerebri. Prolonged prothrombin time with anticoagulants (e.g., warfarin). May interfere with bactericidal action of penicillin. Impaired absorption with antacids containing Al, Ca, or Mg, oral Zn, Fe salts, and bismuth preparations. Increased metabolism with phenobarbital, carbamazepine, primidone and phenytoin. Risk of breakthrough bleeding with oral contraceptives. Increased plasma concentration of ciclosporin. Decreased half-life with hepatic enzyme inducers (e.g., rifampicin). Potentially fatal renal toxicity with methoxyflurane.

It is unsafe to consume alcohol with Doxycycline.

Doxycycline is unsafe during pregnancy as there is definite evidence of risk to the developing baby. However, the doctor may rarely prescribe it in some life-threatening situations if benefits outweigh risks.

Doxycycline is probably safe during breastfeeding. Limited human data suggests no significant risk to the baby.

Contraindicated in children under 8 years of age (risk of permanent tooth discoloration and bone growth effects).

Limited information available regarding dose adjustment for elderly patients. Use with caution.

Renal impairment: Safe in kidney disease. No dose adjustment recommended.

Hepatic impairment: Safe in liver disease. No dose adjustment recommended.

Overdose may cause severe nausea, vomiting, diarrhea and allergic reactions. Provide symptomatic treatment.

Store in a cool and dry place, protected from light. Keep out of reach of children.

Doxycycline