Doxycycline: Antibacterial Drug For Treatment of Undulant Fever or Brucellosis

The gram-negative bacterium called brucella is the known cause of a true zoonotic disease, which is appropriately named brucellosis. The disease usually has an acute beginning, with fever lasting for several days. However, there are no signs that point to any particular part of the body. This early stage is followed by a chronic stage with repeated recurrence of symptoms, including vague pains, weakness, and fever. This is the reason why brucellosis is also sometimes called undulant fever.

There are at least three types of brucella that cause undulant fever. These are brucella abortus (from cattle), brucella melitensis (from goats), and brucella suis (from swine). There are three ways by which brucellosis is spread: by raw milk (or by cheese or butter made from raw milk), by eating the partially cooked meat of an infected animal, or by handling or otherwise coming in contact with the body of such an animal.

Diagnosis of brucellosis requires laboratory tests. The physician may choose from among several antibacterial drugs for treatment. One such antibacterial drug effective against the brucella organism is doxycycline, an example of which is the brand name Vibramycin by Pfizer Inc.

As an antibacterial drug, doxycycline works by interfering with the normal growth cycle of the invading germs. This prevents the bacteria from reproducing, allowing the normal defenses of the body to fight off the infection. This process is called bacteriostatic action. Inasmuch as the action of doxycycline depends on its concentration within the invading organisms, it is necessary that the patient completely follow the physician’s directions.

Nausea, vomiting, stomach upset, skin rash and diarrhea are the common side effects of doxycycline. Less common ones include hairy tongue (lingua villosa), itching, and irritation of the anal region. Consult your physician at once if these symptoms show up. Patients who are on long-term doxycycline should be given periodic laboratory tests and physical examinations.

The usual dose of doxycycline for adults is 200 milligrams, given as 100 milligrams every 12 hours, for the first day. Maintenance dose is 100 milligrams, given in one or two doses. For children, 2 milligrams per pound of body weight divided in two doses (for the first day); maintenance dose is 1 milligram per pound of body weight taken as a single dose per day. An increased occurrence of side effects is observed if the dose exceeds 200 milligrams per day.

Some people with certain conditions are strongly advised against using this antibacterial drug. Examples are those with known liver disease and women who are pregnant. Also as a bacteriostatic drug, doxycycline may interfere with the action of bactericidal agents (example, Penicillin). Hence, it is not advisable to take both medications. The use of doxycycline carries several other cautions; therefore, it is imperative that you seek your physician’s advice before using this antibacterial drug.


1. Definition of Undulant fever –

2. Doxycycline –

3. Doxycycline –

4. Brucella –