Alloprin A , Alloprin, Apo-allopurinol-A , Lopurin, Novopurinol A, Zyloprim
Classifications: antigout agent; Therapeutic: antigout
Pregnancy Category: C
100 mg, 300 mg tablets; 500 mg vial
Allopurinol reduces endogenous uric acid by selectively inhibiting action of xanthine oxidase, the enzyme responsible for
converting hypoxanthine to xanthine and xanthine to uric acid (end product of purine catabolism). Has no analgesic, antiinflammatory,
or uricosuric actions.
Thus, urate pool is decreased by the lowering of both serum and urinary uric acid levels, and hyperuricemia is prevented.
To control primary hyperuricemia that accompanies severe gout and to prevent possibility of flare-up of acute gouty attack;
to prevent recurrent calcium oxalate stones; prophylactically to reduce severity of hyperuricemia associated with antineoplastic
and radiation therapies, both of which greatly increase plasma uric acid levels by promoting nucleic acid degradation.
To reduce hyperuricemia secondary to LeschNyhan syndrome, polycythemia vera, G6PD deficiency, sarcoidosis, and therapy
with thiazides or ethambutol.
Hypersensitivity to allopurinol; as initial treatment for acute gouty attacks; idiopathic hemochromatosis (or those with
family history); children (except those with hyperuricemia secondary to neoplastic disease and chemotherapy); pregnancy (category
Impaired hepatic or renal function, history of peptic ulcer, lower GI tract disease, bone marrow depression.
Route & Dosage
|Treatment of Hyperuricemia
Adult: PO 100 mg/d, may increase by 100 mg/wk (max: 800 mg/d), divide doses >300 mg/d IV 200400 mg/m2/d (max: 600 mg/d) in 14 divided doses
Child: PO ≤10 y, 10 mg/kg/d in 23 divided doses (max: 800 mg/d) IV 200 mg/m2/d in 14 divided doses
Treatment of Secondary Hyperuricemia
Adult: PO 200800 mg/d for 23 d or longer, divide doses >300 mg/d
Child: PO 610 y, 100 mg t.i.d.; <6 y, 50 mg t.i.d.
Clcr 1020 mL/min: 200 mg/d; 310 mL/min: 100 mg qd; <3 mL/min: 100 mg with extended interval between doses (24 h
Dialysis: Administer dose after dialysis or use 50% supplemental dose
- Give after meals for best toleration; tablet may be crushed and taken with fluid or mixed with food.
- Store at 15°30° C (59°86° F) in a tightly closed container.
PREPARE: Intermittent: ?? Reconstitute a single dose vial (500 mg) with 25 mL of sterile water for injection to yield 20 mg/mL.??Must be further diluted with NS or D5W to a concentration of ≤6 mg/mL.?? Note: Adding 2.3 mL of diluent yields 6 mg/mL.
ADMINISTER: Intermittent: Usually administered over 3060 min.
INCOMPATIBILITIES Solution/additive: Amikacin, amphotericin B, carmustine, cefotaxime, chlorpromazine, cimetidine, clindamycin, cytarabine, dacarbazine, daunorubicin, diphenhydramine, doxorubicin, doxycycline, droperidol, floxuridine, gentamicin, haloperidol, hydroxyzine, idarubicin, imipenem-cilastatin, mechlorethamine, meperidine, methylpredinisole, metoclopramide, methylprednisolone, minocycline, nalbuphine, netilmicin, ondansetron, prochlorperazine, promethazine, sodium bicarbonate, streptozocin, tobramycin, vinorelbine.
Adverse Effects (≥1%)CNS:
Drowsiness, headache, vertigo. GI:
Nausea, vomiting, diarrhea, abdominal discomfort, indigestion
, malaise. Hematologic:
(Rare) Agranulocytosis, aplastic anemia, bone marrow depression,
Urticaria or pruritus, pruritic maculopapular rash, toxic epidermal necrolysis. Other: Hepatotoxicity, renal
Diagnostic Test Interference
Possibility of elevated blood levels of alkaline phosphatase and serum transaminases (AST, ALT), and decreased blood Hct, Hgb, leukocytes.
may inhibit renal
excretion of uric acid; ampicillin, amoxicillin
increase risk of skin rash; enhances anticoagulant effect of warfarin;
toxicity from azathioprine, mercaptopurine, cyclophosphamide, cyclosporin
increased; increases hypoglycemic effects of chlorpropamide
increase risk of allopurinol toxicity and hypersensitivity (especially with impaired renal
function); ace inhibitors
increase risk of hypersensitivity; high dose vitamin C increases risk of kidney stone formation.
8090% from GI tract. Onset:
2448 h. Peak:
26 h. Metabolism:
7580% to the active metabolite oxypurinol. Elimination:
Slowly excreted in urine; excreted in breast milk. Half-Life:
13 h; oxypurinol, 1830 h.
Assessment & Drug Effects
- Monitor for therapeutic effectiveness which is indicated by normal serum and urinary uric acid levels usually by 13
wk (aim of therapy is to lower serum uric acid level gradually to about 6 mg/dL), gradual decrease in size of tophi, absence
of new tophaceous deposits (after approximately 6 mo), with consequent relief of joint pain and increased joint mobility.
- Monitor for S&S of an acute gouty attack which is most likely to occur during first 6 wk of therapy.
- Lab tests: Monitor serum uric acid levels q12wk to check adequacy of dosage. Perform baseline CBC, liver and kidney
function tests before therapy is initiated and then monthly, particularly during first few months. Check urinary pH at regular
- Monitor patients with renal disorders more often; they tend to have a higher incidence of renal stones and drug toxicity
- Report onset of rash or fever immediately to physician; withdraw drug. Life-threatening toxicity syndrome can occur 24
wk after initiation of therapy (more common with impaired renal function) and is generally accompanied by malaise, fever,
and aching, a diffuse erythematous, desquamating rash, hepatic dysfunction, eosinophilia, and worsening of renal function.
Patient & Family Education
- Drink enough fluid to produce urinary output of at least 2000 mL/d (fluid intake of at least 3000 mL/d). (Note that 1000
mL is approximately equal to 1 quart.) Report diminishing urinary output, cloudy urine, unusual color or odor to urine, pain
or discomfort on urination.
- Report promptly the onset of itching or rash. Stop drug if a skin rash appears, even after 5 or more wk (and reportedly as
long as 2 y) of therapy.
- Minimize exposure of eyes to ultraviolet or sunlight which may stimulate the development of cataracts.
- Do not drive or engage in potentially hazardous activities until response to drug is known.
- Remain under medical supervision while taking allopurinol (generally continued indefinitely); drug can cause severe adverse