Doxycycline: Uses, Dosage & Side Effects

Doxycycline is a Tetracycline Antibiotic that works by inhibiting bacterial protein synthesis and cell wall formation. This medication is FDA-approved for treating a wide range of infections caused by susceptible organisms. Doxycycline demonstrates excellent tissue penetration and bioavailability, making it suitable for both empiric therapy and targeted treatment approaches. The pharmacokinetics of Doxycycline allow for convenient dosing schedules in most clinical settings.

This antibiotic is widely used in outpatient and inpatient settings due to its favorable safety profile and efficacy against common pathogens. Healthcare providers should consider local resistance patterns when selecting Doxycycline for treatment.

• Infections (respiratory, STI), acne, malaria prophylaxis, Lyme disease
• Community-acquired infections
• Hospital-acquired infections (select organisms)
• Atypical organism infections (Mycoplasma, Chlamydia)
• Prophylaxis in specific patient populations
• Combination therapy for resistant organisms

Broad spectrum: Gram-positive, Gram-negative, atypical organisms, anaerobes

Common resistance in Staphylococcus aureus and some Streptococcus species; variable Gram-negative coverage Clinicians should obtain appropriate cultures and susceptibility testing to guide therapy, particularly in hospitalized patients and those with treatment failure.

Oral Formulations: 100 mg BID for infections; 50-100 mg daily for acne for most indications. Treatment duration varies by infection site and severity (typically 5-14 days).

Intravenous Administration: Available for hospitalized patients requiring parenteral therapy. Dosing typically follows similar principles with adjusted intervals based on renal function.

Special Populations: Renal impairment may require dose adjustment. Hepatic impairment guidelines vary by specific agent; consult prescribing information.

Common: Nausea, diarrhea, abdominal discomfort, headache, photosensitivity (with certain agents)

Serious but Rare: Anaphylaxis, Steven-Johnson syndrome, liver dysfunction, cardiac arrhythmias (QT prolongation with certain agents), Clostridioides difficile colitis

• Known hypersensitivity to the antibiotic or drug class
• Certain drug interactions (check drug interaction tools)
• Specific contraindications vary by formulation and concurrent medications
• Severe renal or hepatic impairment (with dose adjustment possible)

• Antacids may reduce absorption of oral formulations
• Warfarin levels may increase, requiring INR monitoring
• CYP3A4 substrates may require dose adjustment
• Concurrent NSAIDs may increase GI toxicity
• Specific interactions vary; check current drug interaction resources

Randomized controlled trials and clinical experience demonstrate effectiveness of Doxycycline in treating susceptible infections across multiple organ systems. Current treatment guidelines incorporate this agent as a first-line or alternative option depending on local resistance patterns and clinical context.