From the Guidelines
Doxycycline taken by mouth (PO) is effective for treating many bacterial infections, including skin and soft-tissue infections (SSTIs) caused by methicillin-resistant Staphylococcus aureus (MRSA). Doxycycline is a broad-spectrum tetracycline antibiotic that works by inhibiting bacterial protein synthesis, preventing bacteria from growing and multiplying. It is commonly prescribed at doses of 100 mg twice daily or 200 mg once daily for 7-14 days, though duration varies based on the specific infection being treated 1. According to the 2018 WSES/SIS-E consensus conference, doxycycline is one of the recommended oral antibiotics for the management of MRSA skin and soft-tissue infections, along with linezolid, trimethoprim-sulfamethoxazole (TMP-SMX), and tedizolid 1.
Some key points to consider when prescribing doxycycline include:
- Patients should take doxycycline with plenty of water and remain upright for at least 30 minutes after taking it to prevent esophageal irritation.
- Food does not significantly impair absorption, but dairy products, antacids, iron supplements, and calcium supplements can reduce effectiveness, so separate these by at least 2 hours.
- Common side effects include photosensitivity (increased sun sensitivity), nausea, and diarrhea.
- Doxycycline should be avoided in pregnant women and children under 8 years due to potential effects on bone development and tooth discoloration.
- The choice of antibiotic should be based on the severity of the infection, the patient's medical history, and the local epidemiology of antibiotic resistance 1.
In terms of specific infections, doxycycline is particularly effective against:
- Respiratory tract infections
- Urinary tract infections
- Certain sexually transmitted infections (like chlamydia)
- Skin infections
- Some tick-borne diseases such as Lyme disease
- It can also be used for malaria prophylaxis 1.
It's worth noting that while doxycycline is effective against many bacterial infections, it's not effective against all types of bacteria, and the choice of antibiotic should always be guided by culture and susceptibility testing when possible 1.
From the FDA Drug Label
To reduce the development of drug-resistant bacteria and maintain effectiveness of doxycycline hyclate and other antibacterial drugs, doxycycline hyclate should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria Doxycycline is indicated for the treatment of the following infections: Treatment: Doxycycline is indicated for the treatment of the following infections: Rocky Mountain spotted fever, typhus fever and the typhus group, Q fever, rickettsialpox, and tick fevers caused by Rickettsiae.
Doxycycline (PO) is effective for treating certain bacterial infections, including those caused by susceptible bacteria such as:
- Rickettsiae
- Mycoplasma pneumoniae
- Chlamydia trachomatis
- Haemophilus ducreyi
- Yersinia pestis
- Francisella tularensis
- Vibrio cholerae
- Brucella species
- Bartonella bacilliformis
- Calymmatobacterium granulomatis When bacteriologic testing indicates appropriate susceptibility to the drug, doxycycline is also effective against:
- Escherichia coli
- Enterobacter aerogenes
- Shigella species
- Acinetobacter species
- Haemophilus influenzae
- Klebsiella species
- Streptococcus pneumoniae
- Bacillus anthracis 2
From the Research
Effectiveness of Doxycycline PO
- Doxycycline displays excellent activity against gram-positive and gram-negative aerobic and anaerobic pathogens 3.
- The oral absorption of doxycycline is rapid and virtually complete, and serum concentrations following oral administration are comparable to those after intravenous administration 3.
- Doxycycline has been shown to be highly effective in treating various infections, including respiratory tract infections, skin and soft tissue infections, and genitourinary infections 3, 4.
- A study comparing doxycycline and azithromycin for the treatment of rectal Chlamydia trachomatis infection found that doxycycline was superior to azithromycin in a real-world setting 5.
- Doxycycline prophylaxis has also shown promise in preventing bacterial sexually transmitted infections, with high efficacy found in small short-term randomized controlled trials 6.
Key Findings
- Doxycycline is effective against a wide range of bacterial pathogens 3.
- Oral doxycycline is well-absorbed and has a prolonged half-life, allowing for once-daily administration 3.
- Doxycycline has been shown to be effective in treating various types of infections, including respiratory tract infections and genitourinary infections 3, 4.
- Doxycycline may be superior to azithromycin for the treatment of rectal Chlamydia trachomatis infection 5.
- Doxycycline prophylaxis may be effective in preventing bacterial sexually transmitted infections, but more research is needed 6.
Study Results
- A pan-European multi-centre trial found that doxycycline was effective in treating respiratory tract infections, with 87% of patients achieving good or very good results 4.
- A study comparing doxycycline and azithromycin for the treatment of rectal Chlamydia trachomatis infection found that 95.8% of patients treated with doxycycline were cured, compared to 83.7% of patients treated with azithromycin 5.
- A review of doxycycline prophylaxis for bacterial sexually transmitted infections found that two small short-term randomized controlled trials showed high efficacy, but more research is needed to fully understand the effectiveness of doxycycline prophylaxis 6.