Salicylates: Generic and Brand Names
- aspirin (Bayer, Empirin)
- balsalazide (Colazal)
- choline magnesium trisalicylate (Tricosal)
- diflunisal (Dolobid)
- mesalamine (Pentasa)
- olsalazine (Dipentum)
- salsalate (Argesic)
- sodium thiosalicylate (Rexolate, Tusal)
Disease Spotlight: Diseases with Chronic Inflammatory Response
The inflammatory response is a nonspecific reaction to cellular injury that activates chemical mediators and neutrophils to destroy disease-causing organisms and promote healing. It presents as heat (calor), redness (rubor), swelling (tumor), and pain (dolor). In neoplasms, viral invasions, autoimmune diseases, and transplant rejection, that response turns chronic, with increased damage and more severe reactions.
Therapeutic Action
Salicylates inhibit synthesis of prostaglandin, a mediator of the inflammatory reaction. The antipyretic effect comes from blocking the prostaglandin mediator of pyrogens (chemicals released by active white blood cells that raise body temperature) at the thermoregulatory center of the hypothalamus. Aspirin at low levels reduces platelet aggregation by inhibiting synthesis of thromboxane A2, a potent vasoconstrictor that normally promotes platelet aggregation and clot formation; at higher levels it inhibits synthesis of prostacyclin, a vasodilator that inhibits platelet aggregation.
Indications
Mild to moderate pain, fever, and numerous inflammatory conditions (rheumatoid arthritis and osteoarthritis). Mesalamine and balsalazide treat ulcerative colitis and other inflammatory bowel conditions in adults. Sodium thiosalicylate treats arthritis and muscular pain.
By age group: in children, confirm the correct dose because this group is more susceptible to GI and CNS effects, and most of these drugs are OTC, so teach caregivers to read the label for the right dose. Aspirin and choline magnesium trisalicylate are the salicylates recommended for children, but both are contraindicated when there is risk for Reye Syndrome. Acetaminophen is the most used anti-inflammatory in children; overdose causes severe hepatotoxicity. Several NSAIDs are approved for children, including ibuprofen, naproxen, tolmetin, meloxicam, and indomethacin in some cases. In adults, watch for these drugs hidden in OTC products and have patients report OTC use when on any prescription drug to avoid interactions and masked disease. African American patients have a documented decreased sensitivity to the analgesic effect and an increased risk of GI adverse effects, so teach the signs of GI bleeding and monitor closely. In pregnant and nursing women, use is justified only when benefits clearly outweigh the risks. In older adults, adjust the dose for greater susceptibility to GI and CNS effects; naproxen, ketorolac, and ketoprofen carry geriatric warnings for increased toxicity and should be avoided if possible, and gold salts (a treatment for arthritis) are particularly toxic in older patients, causing renal, GI, and liver problems.
Pharmacokinetics
Here are the characteristic interactions of salicylates and the body in terms of absorption, distribution, metabolism, and excretion:
| Route | Onset | Peak | Duration |
|---|---|---|---|
| Oral | 5-30 min | 0.25-2 h | 3-6 h |
| Rectal | 1-2 h | 4-5 h | 6-8 h |
| Half-life (T1/2) | Metabolism | Excretion |
|---|---|---|
| 15 min-12 h | Liver | Urine |
Contraindications and Cautions
Allergy to salicylates, NSAIDs, or tartrazine (a dye with cross-sensitivity to aspirin). Bleeding abnormalities, from changes in platelet aggregation. Impaired renal function, since the drug is excreted in urine. Chickenpox or influenza, for the risk of Reye Syndrome in children and teenagers. The FDA requires a Reye's syndrome warning on OTC aspirin and nonaspirin salicylate products, and the CDC, FDA, and American Academy of Pediatrics advise that aspirin and aspirin-containing products not be given to anyone younger than 19 during a fever-causing illness (FDA final rule; CDC Surgeon General advisory). Surgery or other invasive procedures within 1 week, for increased bleeding risk. Pregnancy and lactation.
Adverse Effects
GI: nausea, dyspepsia, heartburn, epigastric discomfort. Hematologic: blood loss, bleeding abnormalities.
WARNING: Salicylism can occur with high aspirin levels, marked by dizziness, ringing in the ears, difficulty hearing, nausea, vomiting, diarrhea, mental confusion, and lassitude.
WARNING: Acute salicylate toxicity occurs at doses of 20-25 g in adults or 4 g in children. Signs include hyperpnea, tachypnea, hemorrhage, excitement, confusion, pulmonary edema, convulsions, tetany, metabolic acidosis, fever, coma, and cardiovascular, renal, and respiratory collapse.
Interactions
Anticoagulants increase the risk of bleeding. NSAIDs show increased serum levels. Activated charcoal decreases salicylate absorption. Antacids decrease salicylate effects. Carbonic anhydrase inhibitors increase the risk of salicylism.
Nursing Considerations
Screen for the cautions and contraindications above (allergy to salicylate or tartrazine, renal disease, bleeding disorders, pregnancy, lactation) and establish a baseline. Assess skin for lesions, monitor temperature to gauge antipyretic effect, evaluate CNS status, and check pulse, blood pressure, and perfusion for bleeding or cardiovascular effects. Evaluate respirations and adventitious sounds and monitor liver and bowel sounds for hypersensitivity, bleeding, and GI effects. Monitor labs (CBC, liver and renal function, urinalysis, stool guaiac, clotting times) for bleeding and for changes that affect metabolism and excretion. Give the drug with food to ease GI effects. Check every drug the patient takes for salicylate ingredients to avoid toxic levels. Watch for severe reactions and be ready with emergency care (gastric lavage, induced vomiting). Keep the patient well hydrated to lower toxicity risk, and provide supportive comfort measures. Teach drug effects and the warning signs to report. Evaluate against relief of inflammation, and watch for GI upset, CNS changes, and bleeding.
Frequently Asked Questions
Why should aspirin be avoided in children and teenagers? Salicylates are linked to Reye's syndrome, a rare but serious condition that affects the liver and brain. The FDA requires a Reye's syndrome warning on OTC salicylate products, and the CDC, FDA, and American Academy of Pediatrics advise against giving aspirin to anyone younger than 19 during a fever-causing illness like chickenpox or flu.
How do salicylates relieve pain, fever, and inflammation? They inhibit prostaglandin synthesis, the mediator of the inflammatory response. The antipyretic effect comes from blocking prostaglandin-driven pyrogens at the hypothalamic thermoregulatory center.
Why does low-dose aspirin thin the blood? At low levels, aspirin reduces platelet aggregation by inhibiting synthesis of thromboxane A2, a vasoconstrictor that normally promotes clotting.
What is salicylism? Salicylism is a toxic reaction to high aspirin levels marked by dizziness, ringing in the ears, hearing difficulty, nausea, vomiting, diarrhea, confusion, and lassitude.
At what dose does acute salicylate toxicity occur? Acute toxicity occurs at roughly 20 to 25 g in adults or 4 g in children, producing hyperpnea, hemorrhage, confusion, pulmonary edema, seizures, metabolic acidosis, and potential cardiovascular, renal, and respiratory collapse.
Why ask patients what other medicines they take? Salicylates appear in many OTC products, so a patient may unknowingly take the same drug in several bottles. Checking every product helps prevent accidental overdose and masked symptoms.