Acetohydroxamic acid

What is Acetohydroxamic acid?

• Acetohydroxamic acid (Lithostat) is a potent and irreversible enzyme inhibitor of the urease enzyme in various bacteria and plants used as adjunctive therapy in patients with chronic urea-splitting urinary infection.
• It is also known as AHA.

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Acetohydroxamic acid

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What are the uses of this medicine?

• Acetohydroxamic acid (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.
• 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.

How does this medicine work?

• Acetohydroxamic acid reversibly inhibits the bacterial enzyme urease, thereby inhibiting the hydrolysis of urea and production of ammonia in urine infected with urea-splitting organisms.
• The reduced ammonia levels and decreased pH enhance the effectiveness of antimicrobial agents and allow an increased cure rate of these infections.

Who Should Not Use this medicine ?

This medicine cannot be used in patients:

• whose physical state and disease are amenable to definitive surgery and appropriate antimicrobial agents
• whose urine is infected by non-urease producing organisms
• whose urinary infections can be controlled by culture-specific oral antimicrobial agents
• whose renal function is poor (i.e., serum creatinine more than 2.5 mg/dl and/or creatinine clearance less than 20 ml/min)
• who do not evidence a satisfactory method of contraception
• patients who are pregnant

What drug interactions can this medicine cause?

• Tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take.
• Be sure to mention any of the following:
• Drugs that contain iron

• 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.
• AHA taken in association with alcoholic beverages has resulted in a rash.

Is this medicine FDA approved?

• In 1983 the US Food and Drug Administration approved acetohydroxamic acid (AHA) as an orphan drug for "prevention of so-called struvite stones" under the newly enacted Orphan Drug Act of 1983.

How should this medicine be used?

Recommended dosage:

• One tablet 3-4 times a day in a total daily dose of 10-15 mg/kg/day. The recommended starting dose is 12 mg/kg/day, administered at 6-8 hour intervals at a time when the stomach is empty.
• The maximum daily dose should be no more than 1.5 grams, regardless of body weight.
• The dosage should be reduced in patients with reduced renal function. Patients whose serum creatinine is greater than 1.8 mg/dl should take no more than 1.0 gm/day; such patients should be dosed at q-12-h intervals.
• Patients with advanced renal insufficiency (i.e., serum creatinine more than 2.5 mg/dl) should not be treated with AHA.

In children:

• In children an initial dose of 10 mg/kg/day is recommended.

Administration:

• AHA should be administered orally at 6-8 hour intervals at a time when the stomach is empty.

What are the dosage forms and brand names of this medicine?

This medicine is available in fallowing doasage form:

• As 250 mg tablets.

This medicine is available in fallowing brand namesː

• Lithostat

What side effects can this medication cause?

• The most common side effects of this medicine include:
• headaches, abdominal discomfort, nausea, loss of hair, shakiness, and anemia.
• A flushing skin reaction (i.e., redness, warmth, and tingling) has occurred in several patients who consumed alcohol during treatment with Lithostat.
• Lithostat ® thus must be considered a potential human carcinogen.

What special precautions should I follow?

• A Coombs negative hemolytic anemia has occurred in patients receiving AHA. Gastrointestinal upset characterized by nausea, vomiting, anorexia and generalized malaise have accompanied the most severe forms of hemolytic anemia. A complete blood count, including a reticulocyte count, is recommended after two weeks of treatment. A CBC and reticulocyte count are recommended at 3-month intervals for the duration of treatment.
• Bone marrow depression (leukopenia, anemia, and thrombocytopenia) has occurred in experimental animals receiving large doses of AHA. clinical monitoring of the platelet and white cell count is recommended.
• Abnormalities of liver function have not been reported to date. Therefore, close monitoring of liver function is recommended.
• Since AHA is eliminated primarily by the kidneys, patients with significantly impaired renal function should be closely monitored, and a reduction of daily dose may be needed to avoid excessive drug accumulation.

What to do in case of emergency/overdose?

Symptoms of overdosage may include:

• anorexia, malaise, lethargy, diminished sense of well being, tremulousness, anxiety, nausea and vomiting.

• Laboratory findings are likely to include an elevated reticulocyte count and a severe hemolytic reaction requiring hospitalization, symptomatic treatment, and possibly blood transfusions. Concomitant reduction in platelets and/or white blood cells should be anticipated.

Management of overdosage: Recommended treatment for an overdosage reaction consists of (1) cessation of treatment, (2) close monitoring of hematologic status, (3) symptomatic treatment, and (4) blood transfusions as required by the clinical circumstances.

• The drug is probably dialyzable, but this property has not been tested clinically.

Can this medicine be used in pregnancy?

• Pregnancy Category X.
• Acetohydroxamic acid may cause fetal harm when administered to a pregnant woman.
• AHA is contraindicated in women who are or may become pregnant.

Can this medicine be used in children?

• Children with chronic, recalcitrant, urea-splitting urinary infection may benefit from treatment with AHA.
• Children have tolerated a dose of 10 mg/kg/day, taken in two or three divided doses, satisfactorily for periods up to one year.
• Close monitoring of such patients is mandatory.

What are the active and inactive ingredients in this medicine?

Active ingredients:

• ACETOHYDROXAMIC ACID

Inactive ingredient:

• CELLULOSE, MICROCRYSTALLINE
• SILICON DIOXIDE
• MAGNESIUM STEARATE
• PEPPERMINT OIL

Who manufactures and distributes this medicine?

• MISSION PHARMACAL COMPANY, San Antonio, TX

What should I know about storage and disposal of this medication?

• Lithostat should be stored in a dry place at room temperature, 15° - 30°C (59° - 86°F).
• Container should be closed tightly.

• Dailymed label info on Acetohydroxamic acid
• FDA Acetohydroxamic acid

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