PATIENT INFORMATION

PLEASE READ THIS INFORMATION BEFORE USING THIS DRUG.

GENERAL INFORMATION:It has been known for many years that urinary infection may cause the formation of urinary stones. As these stones form, bacteria are trapped within the stones. The trapped bacteria cause the stones to grow, and the stones protect the bacteria from antibiotics. Surgical removal of the stone attempts to break this vicious cycle - many times successfully. However, if infection persists or if a small stone fragment persists, then there is an increased risk of stone recurrence. Multiple operations to remove kidney stones may result in damage and scarring of the kidney. In some situations removal of the kidney may be necessary.

In some instances stones may form initially as a result of non-infectious (i.e., metabolic) causes. If a metabolic stone becomes infected, then an “infection stone” may grow onto the “metabolic stone.” Stone analysis and/or biochemical tests will usually determine which factors are present.

Experimental investigations have identified an enzyme called urease which is made by some (but not all) bacteria. Urease reacts with urine to make ammonia. Ammonia changes the acidity of the urine and the change in acidity encourages stone formation. LITHOSTAT (acetohydroxamic acid) inhibits urease and thereby reduces urinary ammonia. In some instances, LITHOSTAT enhances the effectiveness of antibiotics and thereby makes urinary infection easier to control.
WHAT IS LITHOSTAT? LITHOSTAT is a drug which prevents the excessive buildup of ammonia in your urine, which controls the acidity and alkalinity (pH) of your urine. The cause of excessive ammonia and alkalinity in your urine is a bacterial infection.

WHAT CAN LITHOSTAT DO? Treatment with LITHOSTAT ®is prescribed to decrease urinary ammonia. This may increase the chance of controlling your infection with antibiotics and may help the treatment of your kidney stones. Dissolution of existing stones is unlikely.

LITHOSTAT should not be used in place of surgical treatment. Surgical removal of all stones and elimination of all infection with antibiotics offers the possibility of curative treatment. LITHOSTAT is likely to be more effective after large stones or obstructing stones have been removed.

WHAT ARE THE PROBLEMS OR SIDE EFFECTS WITH LITHOSTAT? The complete spectrum of side effects induced by LITHOSTAT (acetohydroxamic acid) is unknown. However, some side effects which have been reported to date have been headaches, abdominal discomfort, nausea, loss of hair, shakiness, and anemia. Lifethreatening problems (blood clot in the legs) occurred in several patients with advanced disease in early investigation. In more extensive later investigations, this problem has not occurred. No patient has died as a consequence of taking LITHOSTAT. The most serious side effects seem to occur in patients with poor kidney function and/or in patients with a previous history of these conditions.

Problems related to LITHOSTAT have disappeared following cessation of the drug and initiation of appropriate medical treatment. Most patients have resumed treatment without ill effect.

A flushing skin reaction (i.e., redness, warmth, and tingling) has occurred in several patients who consumed alcohol during treatment with LITHOSTAT. The reaction persisted approximately 30 minutes and disappeared without treatment. The cause and significance of this reaction are unknown. Consequently, patients are encouraged to abstain from consumption of alcoholic beverages while being treated with LITHOSTAT.

In animal studies doses of LITHOSTAT about 20 times the maximum human dose have caused fetal abnormalities (birth defects) indicating a potential for such an adverse effect in an exposed human fetus. Therefore, LITHOSTAT should not be given to pregnant women or to any sexually active woman of child-baring age, not using a highly effective method of contraception (oral contraceptive or IUD).

An acceptable long-term study of the cancer causing potential of LITHOSTAT has not been conducted, but a known metabolite of LITHOSTAT, acetamide, is carcinogenic (cancer-causing) to the liver in rats at doses about 80 times the maximum human dose of LITHOSTAT. LITHOSTAT thus must be considered a potential human carcinogen. LITHOSTAT kills tissue cells grown in tissue culture and alters genetic material in cells grown in culture.

LITHOSTAT may induce other adverse reactions which have not yet been recognized.

Unusual symptoms should be reported to your physician. Mild symptoms usually do not warrant discontinuation of treatment. Severe symptoms may necessitate temporary cessation of treatment and/or alteration of dosage.

WHAT ABOUT TAKING OTHER DRUGS WITH LITHOSTAT? Only take those drugs prescribed by your physician. Do not take prescription drugs or over the counter preparations without your physician‘s specific prescription or recommendation. Drugs that contain iron should not be taken at the same time as LITHOSTAT, (acetohydroxamic acid).

LITHOSTAT reacts with iron, and may not be absorbed into the bloodstream. Both the iron you take and the LITHOSTAT you take may be ineffective if both drugs are taken together.

HOW IMPORTANT IS MY DAILY DOSAGE OF LITHOSTAT®?If you fail to follow your daily dosage schedule with LITHOSTAT you will probably suffer a setback in treatment effectiveness and new kidney stone formation is likely. LITHOSTAT plus antibiotic therapy must be taken exactly as your physician prescribes it for optimum effectiveness.

IN CONCLUSION:Your daily dosage of LITHOSTAT (acetohydroxamic acid) is important to the proper treatment of your condition. Any unusual side effects should be reported to your physician at once.

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MISSION PHARMACAL COMPANY, San Antonio, TX 78230 1355

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