Lithostat

Lithostat

 [lith´o-stat]
trademark for a preparation of acetohydroxamic acid, a urease inhibitor used in treatment of kidney stones and urinary tract infections.

acetohydroxamic acid

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

AHA

(trade name),

Lithostat

(trade name)

Classification

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

Indications

Adjunct therapy in chronic urea-splitting urinary tract infection.

Action

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.

Pharmacokinetics

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)

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

Contraindications/Precautions

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)

Cardiovascular

  • palpitations
  • superficial phlebitis of the lower extremities

Dermatologic

  • alopecia
  • rash (in association with alcohol)

Gastrointestinal

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

Hematologic

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

Interactions

Drug-Drug interaction

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

Route/Dosage

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).

Availability

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)

Implementation

  • 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.

Lithostat

(lĭth′ə-stăt′)
A trademark for the drug acetohydroxamic acid.

Lithostat

[lith′ostat]
a trademark for a preparation of a urease inhibitor used in treatment of kidney stones and urinary tract infections (acetohydroxamic acid).