trademark for a preparation of acetohydroxamic acid, a urease inhibitor used in treatment of kidney stones and urinary tract infections.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

acetohydroxamic acid

(a-seet-oh-hye-drox-am-ik a-sid) ,


(trade name),


(trade name)


Therapeutic: anti infectives
Pharmacologic: urease inhibitors
Pregnancy Category: X


Adjunct therapy in chronic urea-splitting urinary tract infection.


Reversibly inhibits the bacterial enzyme urease, which results in decreased hydrolysis of urea and subsequent production of ammonia in urine infected with urea-splitting bacteria.

Therapeutic effects

Decreased urinary ammonia levels and decreased urine pH, which increases the efficacy of anti-infective therapy and cure rates.
Does not directly alter pH or have any direct antibacterial activity.


Absorption: Well absorbed following oral administration.
Distribution: Distributed throughout body water.
Metabolism and Excretion: 36–65% excreted unchanged in urine.
Half-life: 5–10 hr (increased in renal impairment).

Time/action profile (effect on urine)

PO4–8 hrs0.25–1 hr†6–8 hr
†Blood levels


Contraindicated in: Urinary tract infection with non-urea-splitting organisms; Urinary tract infections that can be controlled by culture-specific oral antibiotics; Serum creatinine >2.5 mg/dL or CCr <20 mL/min; Obstetric: Causes birth defects; women of childbearing potential must use adequate contraception; Lactation: Safety not established.
Use Cautiously in: Renal impairment (increased risk of adverse reactions; dosage reduction recommended); Hepatic impairment; Pre-existing thrombophlebitis or phlebothrombosis (increased risk of adverse reactions).

Adverse Reactions/Side Effects

Central nervous system

  • headache (most frequent)
  • anxiety (most frequent)
  • depression (most frequent)
  • malaise (most frequent)
  • nervousness (most frequent)
  • tremulousness (most frequent)


  • palpitations
  • superficial phlebitis of the lower extremities


  • alopecia
  • rash (in association with alcohol)


  • anorexia, (most frequent)
  • nausea, (most frequent)
  • vomiting (most frequent)


  • anemia (most frequent)
  • hemolytic anemia (most frequent)


Drug-Drug interaction

Decreases absorption of iron.Iron decreases the absorption of acetohydroxamic acid.Concurrent ingestion of alcohol increases the incidence of rash.


Oral (Adults) 250 mg 3–4 times daily (total dose 10–15 mg/kg/day)(maximum daily dose = 1500 mg).
Oral (Children) 10 mg/kg/day in divided doses; further titration may be necessary.

Renal Impairment

Oral (Adults) Serum creatinine 1.8–2.5 mg/dL—do not exceed 1000 mg/day (given at 12 hr intervals; further adjustments may be necessary).


Tablets: 250 mg

Nursing implications

Nursing assessment

  • Assess patient for signs and symptoms of urinary tract infection (frequency, urgency, fever, pus in urine) throughout therapy.
  • Lab Test Considerations: Monitor CBC including reticulocyte count after 2 wk of treatment and every 3 mo during therapy. Reticulocytosis and hemolytic anemia may occur. If reticulocyte count is >6%, reduce dose.
    • Monitor renal and hepatic function closely during therapy.

Potential Nursing Diagnoses

Risk for infection (Indications)
Impaired urinary elimination (Indications)


  • If a patient requires iron for a microcytic anemia, intramuscular iron can be used during the course of treatment with acetohydroxamic acid.
  • Oral: Administer on an empty stomach, 1 hr before or 2 hr after meals.

Patient/Family Teaching

  • Instruct patient to take medication exactly as directed.
  • Inform patient that mild headache may occur during first 48 hr of treatment. Headaches usually respond to oral salicylates (aspirin) and usually disappear spontaneously.
  • Advise patient that taking acetohydroxamic acid concurrently with alcohol may cause a nonpruritic macular skin rash to occur on upper extremities and face. Rash usually appears 30–45 min after ingestion of alcohol and may be associated with a sensation of warmth. It usually spontaneously disappears in 30–60 min.
  • Emphasize the importance of periodic lab tests to monitor for side effects.
  • Caution patients of childbearing potential to use a reliable form of contraception while taking acetohydroxamic acid.

Evaluation/Desired Outcomes

  • Decreased urinary ammonia levels and decreased urine pH which increases the efficacy of anti-infective therapy and cure rates in urinary tract infections.
Drug Guide, © 2015 Farlex and Partners


A trademark for the drug acetohydroxamic acid.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
References in periodicals archive ?
* Acetohydroxamic acid (Lithostat) for infection stones (struvite stones) that cannot be removed.