Kidney Stone Photos

Lithostat® is a prescription drug that prevents the excessive build-up of ammonia in your urine to control its acidity and alkalinity (pH). It may improve the effectiveness of antibiotics and help increase the cure rate in patients treated for chronic urea-splitting urinary infection.

Important Safety Information

Lithostat® should not be used in place of surgery. Surgical removal of all kidney stones, combined with antibiotics that eliminate the infection causing the stones, will provide the best chance for a cure. Lithostat® is more effective after removal of large struvite stones or stones that become lodged in the urinary tract.

Lithostat® is not for everyone. You should not take Lithostat® if your health and physical condition are a good fit for surgery and appropriate antibiotics.

Do not take Lithostat® if you are pregnant, may become pregnant, or are breastfeeding. Lithostat® contains acetohydroxamic acid (AHA), which has been linked to birth defects in laboratory animals and may cause harm to your unborn child. Some drugs can pass to infants through breast milk, and there may be serious side effects from AHA, so you should stop nursing if you are taking Lithostat®.

Do not take Lithostat® if you have poor kidney function, if your urine is infected by organisms that do not produce the enzyme urease, or if your infection can be controlled by culture-specific antimicrobial agents (antibiotics that prevent the specific type of bacteria causing your infection).

Do not take other prescription drugs or over the counter medications while you are taking Lithostat®, unless you are directed to do so by your doctor. In particular, do not take any medications that contain iron, because Lithostat® reacts with iron and both the iron and the Lithostat® may become ineffective.

AHA is eliminated primarily by the kidneys, so if you have reduced kidney function, your doctor will closely monitor you and may decrease your dosage of Lithostat® to avoid excessive build up of AHA in your system.

Liver problems have not been reported with Lithostat®. However, a compound related to AHA caused significant problems in an unrelated study, so your doctor will need to monitor your liver function.

For best results, you must take Lithostat® plus antibiotic therapy exactly as your physician prescribes it. If you don't follow your daily dosage schedule, your treatment will be less effective, and you will be likely to form new stones.

Patients that drank alcohol while taking Lithostat® have reported a flushing skin reaction (redness, warmth, and tingling), which lasted approximately 30 minutes. The reaction disappeared without treatment, however, its cause and significance are unknown, so you should not drink alcohol while taking Lithostat®.

Lithostat® may cause unknown side effects. Some reported side effects include headaches, abdominal discomfort, nausea, hair loss, shakiness, and anemia (a reduction in red blood cells). In early research, life-threatening problems (blood clot in the legs) occurred in several patients with advanced disease.

However, in more extensive, later research, these problems have not occurred. No patient has died because of taking Lithostat®. The most serious side effects seem to occur in patients with poor kidney function or those with a previous history of these conditions.

An abnormal breakdown of red blood cells (called a Coombs negative hemolytic anemia) has occurred in some patients taking AHA. The most severe forms of this condition were accompanied by gastrointestinal symptoms, such as nausea, vomiting, loss of appetite, and a general feeling of discomfort. Some patients had only laboratory findings of an anemia; however, most developed a mild reticulocytosis (an increase in immature red blood cells). The negative effects of Lithostat® disappeared after patients stopped taking the drug and began appropriate medical treatment.

Bone marrow depression (a decrease in white blood cells, red blood cells, or platelets) has occurred in laboratory animals receiving large doses of AHA; however, this has not yet been seen in humans.

There have not been acceptable long-term studies of the cancer-causing potential of Lithostat®. However, Lithostat® alters genetic material and kills tissue cells grown in lab tests. High doses of acetamide, a compound related to Lithostat®, are associated with liver cancer in laboratory rats. Therefore, Lithostat® may have the potential to cause cancer in humans.

Always report any unusual side effects to your doctor immediately. Mild symptoms usually do not call for stopping treatment. Severe symptoms may require that you stop treatment temporarily and/or change your dosage.

To report negative side effects, contact Mission Pharmacal Company at 1-800-298-1087 or the FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.