In the U.S.—

In Canada—

• Antiprotozoal

Atovaquone ( a-TOE-va-kwone) is used to treat and to prevent Pneumocystis carinii (noo-moe-SISS-tis ) pneumonia (PCP), a very serious kind of pneumonia. This particular kind of pneumonia occurs commonly in patients whose immune systems are not working normally, such as cancer patients, transplant patients, and patients with acquired immune deficiency syndrome (AIDS).

This medicine is available only with your doctor's prescription, in the following dosage form:

Oral
• Oral suspension (U.S.)
• Tablets (Canada)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For atovaquone, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to atovaquone. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Diet—Make certain your health care professional knows if you are on any special diet. This medicine must be taken with balanced meals so that it can work properly.

Pregnancy—Atovaquone has not been studied in pregnant women. However, studies in rabbits have shown an increase in miscarriages and other harmful effects in the mother and fetus. Before taking this medicine, make sure your doctor knows if you are pregnant or if you may become pregnant.

Breast-feeding—It is not known whether atovaquone passes into human breast milk. However, it was found in the milk of rats. Be sure you have discussed the risks and benefits of atovaquone with your doctor.

Children—Atovaquone has been tested in a limited number of children 1 month of age to 13 years old. It is not known if this medicine causes different side effects or problems in children than it does in adults.

Older adults—Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults or if they cause different side effects or problems in older people. There is no specific information comparing use of atovaquone in the elderly with use in other age groups.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking atovaquone, it is especially important that your health care professional know if you are taking any of the following:

• Rifampin (e.g., Rifadin)—Use of rifampin with atovaquone may decrease the amount of atovaquone in the blood and keep it from working properly

• Stomach or intestinal disorders—Atovaquone may not work properly in patients with some kinds of stomach or intestinal problems

It is important that you take atovaquone with a balanced meal. This is to make sure the medicine is fully absorbed into the body and will work properly.

Atovaquone tablets may be crushed if necessary to make it easier to swallow the tablets.

Because atovaquone tablets and oral suspension do not produce the same amount of medicine in the blood, the tablets and the suspension cannot be switched and used in place of each other.

For patients taking the oral liquid form of this medicine:

• This medicine is to be taken by mouth. Use a specially marked measuring spoon or other device to measure each dose accurately. The average household teaspoon may not hold the right amount of liquid.
• Do not use after the expiration date on the label since the medicine may not work properly after that date. Check with your pharmacist if you have any questions about this.

To help clear up your infection completely, keep taking your medicine for the full time of treatment, even if you begin to feel better after a few days. If you stop taking this medicine too soon, your symptoms may return.

Atovaquone works best when there is a constant amount in the blood. To help keep the amount constant, do not miss any doses.

Dosing—

The dose of atovaquone may be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of atovaquone. If your dose is different, do not change it unless your doctor tells you to do so.

• For treatment of Pneumocystis carinii pneumonia (PCP):
  • For oral suspension dosage form:
    • Adults and teenagers—750 milligrams (mg) taken with a meal two times a day for twenty-one days.
    • Children—Use and dose must be determined by your doctor.
  • For tablet dosage form:
    • Adults and teenagers—750 mg taken with a meal three times a day for twenty-one days.
    • Children—Use and dose must be determined by your doctor.

• For prevention of Pneumocystis carinii pneumonia (PCP):
  • For oral suspension dosage form:
    • Adults and teenagers—1500 milligrams (mg) once a day with a meal.
    • Children—Use and dose must be determined by your doctor.

Missed dose—

If you miss a dose of this medicine, take it as soon as possible. This will help to keep a constant amount of medicine in the blood. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage—

To store this medicine:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Do not store in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down.
• Do not keep outdated medicine or medicine no longer needed. Be sure that any discarded medicine is out of the reach of children.
• Do not freeze.

If your symptoms do not improve within a few days, or if they become worse, check with your doctor.

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

• More common
  • Fever;  skin rash 
  
  

Other side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. However, check with your doctor if any of the following side effects continue or are bothersome:

• More common
  • Cough;  diarrhea;  headache;  nausea;  trouble in sleeping;  vomiting 
  
  

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.