What is Doxycycline used to treat?

As with any antibiotic, Doxycycline is only effective in the treatment of sickness caused by vulnerable bacteria. Although it is classified as a broad-spectrum antibiotic, i.e. it is effective against several different types of bacteria, its effect is limited to those bacteria. If you take this drug and laboratory testing later shows your infection is caused by a different bacterium, this drug will be completely ineffective. You will have to switch to the correct antibiotic or antiviral drug, i.e. your original antibiotic will have absolutely no effect if you have fallen prey to a virus. That means it is very important to get a proper diagnosis from your doctor before you take any antibiotic. Doctors have local knowledge and know whether there are local trends suggesting a common cause (the epidemiology and susceptibility patterns). Trusting the name and taking Doxycycline without a doctor’s approval may make the drug less effective for you in later use, i.e. all the bacteria that survive your first self-administered treatment, will be more resistant the second time when you actually need it to work.

What follows is not a complete list of the vulnerable bacteria and the diseases they cause, but it indicates the general range of sickness that will respond to treatment with Doxycycline. There are a range of gram-negative infections caused by the Rickettsia bacteria. These are transferred to humans through parasites such as fleas, lice and ticks. They include the infections in the typhus group, rickettsialpox, Q. Fever and the most dangerous Rocky Mountain Spotted Fever.

There are then a series of different gram-negative infections of the respiratory tract including Mycoplasma pneumoniae, Haemophilus influenzae and Klebsiella (which also causes urinary tract infections). Similarly, the gram-positive Streptococcus pneumonie is also susceptible. Note that there is no single cause of pneumonia. Worse, some different conditions such as psittacosis may also present as acute pneumonia. This reinforces the need to make the right choice of the antibiotic to treat the infection.

Many of the sexually transmitted diseases caused by bacteria and falling within the general class of chlamydia respond well to Doxycycline. These range from trachoma affecting the eyes to the less common Lymphogranuloma venereum which is an infection of the lymph nodes in both men and women. It may also be used to treat some types of gonorrhea and syphilis.

Although not necessarily transmitted sexually, the same bacteria may cause infections of the urethra, cervix and rectum. Doxycycline also treats non-gonococcal urethritis which is an infection of the urethra not caused by sexually transmitted gonorrhea.

The following diseases may respond, again depending on the bacteria responsible:
• anthrax;
• brucellosis (both by contact with animals and eating uncooked or undercooked meat);
• chancroid;
• cholera; and
• plague.

Finally there are the food-borne diseases:
• campylobacter;
• Escherichia coli; and
• Listeria.

Doxycycline may also be used as a preventative measure (prophylaxis) to provide some protection against malaria so long as you do not intend to travel in affected areas for more than three to four months.