Acetohydroxamic Acid

Class and Category

Pharmacologic class: Urease inhibitor

Therapeutic class: Antagonist to bacterial enzyme urease

Indications and Dosages

👉  As an adjunct to antimicrobial therapy to treat chronic UTI caused by urea-splitting bacteria

TABLETS

Adults. Initial: 12 mg/kg daily in divided doses every 6 to 8 hr on an empty stomach. Usual: 250 mg three or four times daily for a total of 10 to 15 mg/kg daily. Maximum: 1,500 mg daily.

Children. Initial: 10 mg/kg daily in divided doses on an empty stomach, increased or decreased as tolerated and needed.

DOSAGE ADJUSTMENT For a patient with a creatinine clearance level above 1.8 mg/dl, dosage interval increased to every 12 hours and maximum daily dosage decreased to 1 g.

Mechanism of Action

Inhibits urease, the enzyme that catalyzes urea’s hydrolysis to carbon dioxide and ammonia in urine infected with urea-splitting bacteria. This action reduces the urine ammonia level and pH, enhancing antimicrobial drug effectiveness.

Contraindications

Contributing disorder that’s treatable by surgery or appropriate antimicrobial therapy, hypersensitivity to acetohydroxamic acid or its components, inadequate renal function (serum creatinine level above 2.5 mg/dl or creatinine clearance below 20 ml/min), risk of pregnancy, UTI caused by nonurease-producing organisms, UTI that could be controlled by appropriate antimicrobial therapy.

Interactions

DRUGS

Iron: Decreased intestinal absorption of iron, decreased effects of iron and acetohydroxamic acid

ACTIVITIES

Alcohol use: Increased risk of severe rash 30 to 45 minutes after drinking alcohol.

Adverse Reactions

CNS: Anxiety, depression, fever, headache, lack of coordination, malaise, nervousness, slurred speech, tiredness, tremor

CV: Deep venous thrombosis, palpitations, superficial phlebitis

EENT: Pharyngitis, sudden change in vision

GI: Anorexia, nausea, vomiting

HEME: Hemolytic anemia, reticulocytosis, unusual bleeding

RESP: Dyspnea, pulmonary emboli

SKIN: Ecchymosis, hair loss, nonpruritic macular rash

Childbearing Considerations

PREGNANCY

Drug may cause serious fetal harm.

Drug is contraindicated in a pregnant woman as well as any childbearing woman who is not using a reliable method of contraception.

LACTATION

It is not known if drug is present in breast milk.

A decision should be made to discontinue breastfeeding or the drug to avoid potential serious adverse reactions in the breastfed infant.

REPRODUCTION

Advise women of childbearing age to use a reliable method of contraception throughout drug therapy.

Nursing Considerations

• Use acetohydroxamic acid cautiously in patients with anemia or chronic renal disease and those who’ve had phlebitis or thrombophlebitis.
• Be aware that risk of adverse psychomotor effects increases if patient drinks alcohol or takes drugs that affect alertness and reflexes, such as analgesics, antihistamines, narcotics, sedatives, and tranquilizers.

WARNING Be aware that acetohydroxamic acid chelates with dietary iron. If patient has iron deficiency anemia, expect to administer I.M. iron as needed during acetohydroxamic acid therapy.

• Monitor follow-up laboratory tests to check hepatic and renal function and urine pH, as ordered.

PATIENT TEACHING

• Instruct patient to take drug at same time each day, as prescribed.
• Tell patient to take a missed dose up to 2 hours after scheduled time. If more than 2 hours have passed, he should wait for next scheduled dose and shouldn’t double that dose.
• Warn patient not to take drug with alcohol or iron and to consult prescriber before taking it with any other drug.
• Instruct patient to avoid hazardous activities during therapy.