|AMINOSALICYLIC ACID (PARA-AMINOSALICYLIC ACID)
Classifications: antituberculosis agent; Therapeutic:antituberculosis agent
Pregnancy Category: C
4 g packets
Aminosalicylic acid and salts are highly specific bacteriostatic agents that suppress growth and multiplication of Mycobacterium tuberculosis by preventing folic acid synthesis. Their mechanism of action resembles that of sulfonamides. Aminosalicylates also reportedly
have potent hypolipemic action.
Aminosalicylates are an effective antiinfective alone or in combined therapy and reduce serum cholesterol and triglycerides
by lowering LDL and VLDL.
With streptomycin or isoniazid or both in treatment of pulmonary and extrapulmonary tuberculosis to delay drug resistance.
Documented for lipid-lowering effect.
Hypersensitivity to aminosalicylates, salicylates, or to compounds containing para-aminophenyl groups (e.g., sulfonamides, certain hair dyes), G6PD deficiency, use of the sodium salt in patients on sodium
restriction or CHF; pregnancy (category C); lactation.
Impaired renal and hepatic function; blood dyscrasias; goiter; gastric ulcer.
Route & Dosage
Adult: PO 1012 g/d in 23 divided doses
Child: PO 150300 mg/kg/d in 34 divided doses
- Give with or immediately following meals to reduce irritative gastric effects. Physician may order an antacid to be given
concomitantly. Generally, GI adverse effects disappear after a few days of therapy.
- Store in tight, light-resistant containers in a cool, dry place, preferably at 15°30° C (59°86°
F), unless otherwise directed.
Adverse Effects (≥1%)Body as a Whole:
Fever, chills, generalized malaise
, joint pain, rash, fixed-drug eruptions, pruritus; vasculitis; Loeffler's syndrome
Psychotic reactions. GI: Anorexia, nausea, vomiting, abdominal distress, diarrhea,
peptic ulceration, acute hepatitis
, malabsorption. Hematologic: Leukopenia
eosinophilia, lymphocytosis, thrombocytopenia
, hemolytic anemia
; (G6PD deficiency), prothrombinemia. Urogenital: Renal
(irritation), crystalluria. Other:
With long-term administration
Diagnostic Test Interference
Aminosalicylates may interfere with urine urobilinogen determinations (using Ehrlich's reagent), and may cause false-positive urinary protein and VMA determinations (with diazoreagent); false-positive urine glucose may result with cupric sulfate tests, e.g., Benedict's solution, but reportedly not with glucose oxidase reagents (e.g., TesTape, Clinistix). Reduces serum cholesterol, and possibly serum potassium, serum PBI, and 24-hour I-131 thyroidal uptake (effect may last almost 14 d).
Increases hypoprothrombinemic effects of oral anticoagulants;
increased risk of crystalluria with ammonium chloride, ascorbic acid;
decreased intestinal absorption of cyanocobalamin, folic acid, digoxin; antihistamines
may inhibit PAS absorption; may increase or decrease phenytoin
levels; probenecid, sulfinpyrazone
decrease PAS elimination.
Almost completely from GI tract; sodium form more rapidly absorbed than the acid. Peak:
1.52 h. Duration:
4 h. Distribution:
Well distributed to tissue
and body fluids
except CSF unless meninges are inflamed. Metabolism:
In liver. Elimination:
>80% in urine in 710 h. Half-Life:
Assessment & Drug Effects
- Monitor for abrupt onset of fever, particularly during the early weeks of therapy, and clinical picture resembling that
of infectious mononucleosis (malaise, fatigue, generalized lymphadenopathy, splenomegaly, sore throat), as well as minor
complaints of pruritus, joint pains, and headache, which strongly suggest hypersensitivity; report these symptoms promptly.
- Monitor I&O and encourage fluids. High concentrations of drug are excreted in urine, and this can cause crystalluria and
- Note: To minimize crystalluria, keep urine neutral or alkaline with adjunctive drugs, such as antacids or with diet.
Patient & Family Education
- Rinse mouth with clear water or chew sugar-free gum or candy to relieve the mildly sour or bitter aftertaste of aminosalicylic
- Note: Hypersensitivity reactions may occur after a few days, but most commonly in the fourth or fifth week; report promptly.
- Notify physician if sore throat or mouth, malaise, unusual fatigue, bleeding or bruising occurs (symptoms of blood dyscrasia).
- Note: Therapy generally lasts about 2 y. Adhere to the established drug regimen, and remain under close medical supervision to
detect possible adverse drug effects during the treatment period. Resistant TB strains develop more rapidly when drug regimen
is interrupted or is sporadic.
- Note: Urine may turn red on contact with bleach used in commercial toilet bowl cleaners.
- Do not take aspirin or other OTC drugs without physician's approval.
- Discard drug if it discolors (brownish or purplish); this signifies decomposition.