INDICATIONS: LITHOSTAT® (Acetohydroxamic Acid) is indicated as adjunctive therapy in patients with chronic urea-splitting urinary infection. Long-term treatment with AHA may be warranted to maintain urease inhibition as long as urea-splitting infection is present.
Important Safety Information
LITHOSTAT® is contraindicated in patients:
(a) whose physical state and disease are amenable to definitive surgery and antimicrobials.
(b) whose urine is infected by non-urease producing organisms.
(c) whose urinary infections can be controlled by culturespecific oral antimicrobials.
(d) with poor renal function (i.e., serum creatinine >2.5 mg/dL, CrCl <20 mL/min).
(e) who are pregnant, or who may become pregnant because they are not using a satisfactory method of contraception.
Acetohydroxamic acid (AHA) may cause fetal harm when administered to a pregnant woman (Pregnancy Category X).
WARNINGS & PRECAUTIONS:
- A Coombs negative hemolytic anemia, accompanied by gastrointestinal upset and generalized malaise, can occur: Monitor and obtain CBCs with reticulocytes after 2 weeks of therapy and every 3 months thereafter; if reticulocytes >6%, consider reduced dose
- Bone marrow depression (leukopenia, anemia, and thrombocytopenia) has occurred in laboratory animals at high doses: Monitor platelet and white cell count
- A derivative of AHA caused liver dysfunction in an unrelated study: Monitor liver function
- AHA is eliminated by the kidneys: Monitor patients with significant renal impairment and consider a dose reduction
- It is not known whether AHA is excreted in human milk: Because of the potential for serious adverse events in nursing infants, a decision should be made to discontinue nursing or the drug
- Children with chronic, resistant urea-splitting urinary infections may benefit from AHA, however detailed studies of dose and dosage intervals have not been conducted. Children have tolerated a dose of 10 mg/kg/day, taken in two or three divided doses for up to one year: Close monitoring is mandatory
Experience with AHA is limited. About 150 patients have been treated, most for periods greater than a year. Adverse reactions are more prevalent in patients with pre-existing thrombophlebitis or phlebothrombosis and/or in patients with advanced renal insufficiency. The risk of adverse events is highest during the first year of treatment. The following reactions have been reported: mild headaches, gastrointestinal symptoms, nausea, vomiting, anorexia, malaise, laboratory findings characteristic of a hemolytic anemia, mild reticulocytosis without anemia, non-pruritic, macular skin rash (usually in conjunction with alcohol ingestion), alopecia, superficial phlebitis of the lower extremities, phlebothrombosis, embolic phenomena including small pulmonary emboli, palpitations, depression, anxiety, tremulousness, and nervousness.
Until wider clinical data are obtained, AHA should be used with caution in patients receiving other therapeutic agents. AHA taken in association with alcoholic beverages may cause a transient rash. When AHA is taken concomitant with dietary iron, absorption of both acetohydroxamic acid and iron may be reduced. When iron is indicated, use the intramuscular form.
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