ASPIRIN

BRAND NAMES:
Arthritis Pain, Aspergum, Aspir-Low, Aspirin Lite Coat, Bayer Aspirin, Bufferin, Easprin, Ecotrin, Empirin, Fasprin, Genacote, Halfprin, Norwich Aspirin, St. Joseph Aspirin, Stanback Analgesic, Tri-Buffered Aspirin, YSP Aspirin, Zorprin

AVAILABLE FORMS:
Chewable tablets: 81mg;
Caplets and tablets: 325mg, 500mg;
Enteric coated (safety coated) caplets and tablets: 325mg, 500mg
Suppositories: 120mg, 200mg, 300mg, 600mg

INDICATIONS:
 Angiotensin Converting Enzyme (ACE) Inhibitors: The hyponatremic and hypotensive effects of ACE inhibitors may be diminished by the concomitant administration of aspirin due to its direct effect on the ennin-angiotensin conversion pathway.
 Acetazolamide: Concurrent use of aspirin and acetazolamide can lead to high serum concentrations of acetazolamide (and toxicity) due to competition at the renal tubule for secretion.
 Anticoagulant Therapy (Heparin and Warfarin): Patients on anticoagulation therapy are at increased risk for bleeding because of drug-drug interactions and the effect on platelets. Aspirin can displace warfarin from protein binding sites, leading to prolongation of both the prothrombin time and the bleeding time. Aspirin can increase the anticoagulant activity of heparin, increasing bleeding risk.
 Anticonvulsants: Salicylate can displace protein-bound phenytoin and valproic acid, leading to a decrease in the total concentration of phenytoin and an increase in serum valproic acid levels.
 Beta Blockers: The hypotensive effects of beta blockers may be diminished by the concomitant administration of aspirin due to inhibition of renal prostaglandins, leading to decreased renal blood flow, and salt and fluid retention.
 Diuretics: The effectiveness of diuretics in patients with underlying renal or cardiovascular disease may be diminished by the concomitant administration of aspirin due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention.
 Methotrexate: Salicylate can inhibit renal clearance of methotrexate, leading to bone marrow toxicity, especially in the elderly or renal impaired.
 Nonsteroidal Anti-inflammatory Drugs (NSAID’s): The concurrent use of aspirin with other NSAID’s should be avoided because this may increase bleeding or lead to decreased renal function.
 Oral Hypoglycemics: Moderate doses of aspirin may increase the effectiveness of oral hypoglycemic drugs, leading to hypoglycemia.
 Uricosuric Agents (Probenecid and Sulfinpyrazone): Salicylates antagonize the uricosuric action of uricosuric agents.
 Carcinogenesis, Mutagenesis, Impairment of Fertility: Administration of aspirin for 68 weeks at 0.5 percent in the feed of rats was not carcinogenic. In the Ames Salmonella assay, aspirin was not mutagenic; however, aspirin did induce chromosome aberrations in cultured human fibroblasts. Aspirin inhibits ovulation in rats. (See Pregnancy.)
 Pregnancy: Pregnant women should only take aspirin if clearly needed. Because of the known effects of NSAID’s on the fetal cardiovascular system (closure of the ductus arteriosus), use during the third trimester of pregnancy should be avoided. Salicylate products have also been associated with alterations in maternal and neonatal hemostasis mechanisms, decreased birth weight, and with perinatal mortality.
 Labor and Delivery: Aspirin should be avoided 1 week prior to and during labor and delivery because it can result in excessive blood loss at delivery. Prolonged gestation and prolonged labor due to prostaglandin inhibition have been reported.
 Nursing Mothers: Nursing mothers should avoid using aspirin because salicylate is excreted in breast milk. Use of high doses may lead to rashes, platelet abnormalities, and bleeding in nursing infants.
 Pediatric Use: Pediatric dosing recommendations for juvenile rheumatoid arthritis are based on well-controlled clinical studies. An initial dose of 90-130 mg/kg/day in divided doses, with an increase as needed for anti-inflammatory efficacy (target plasma salicylate levels of 150-300 mcg/mL) are effective. At high doses (i.e., plasma levels of greater than 200 mg/mL), the incidence of toxicity increases.

ADVERSE REACTION:
EENT: tinnitus, hearing loss.
GI: nausea, GI distress, occult bleeding, dyspepsia, GI bleeding
Hematologic: leucopenia, thrombocytopenia, prolonged bleeding time
Hepatic: hepatitis
Skin: rash, bruising, urticaria.
Other: angioedema, hypersensitivity reactions, Reye’s syndrome

MECHANISM OF ACTION:
Aspirin is in a group of drugs called salicylates. It works by reducing substances in the body that cause pain, fever, and inflammation. Aspirin's ability to suppress the production of prostaglandins and thromboxanes is due to its irreversible inactivation of the cyclooxygenase (COX) enzyme. Cyclooxygenase is required for prostaglandin and thromboxane synthesis. Aspirin acts as an acetylating agent where an acetyl group is covalently attached to a serine residue in the active site of the COX enzyme. This makes aspirin different from other NSAIDs (such as diclofenac and ibuprofen), which are reversible inhibitors. It is thought to produce analgesia by blocking generation of pain impulses and relieve fever by central action in the hypothalamic heat-regulating center.

CONTRAINDICATION:
Allergy: Aspirin is contraindicated in patients with known allergy to nonsteroidal anti-inflammatory drug products and in patients with the syndrome of asthma, rhinitis, and nasal polyps. Aspirin may cause severe urticaria, angioedema, or bronchospasm (asthma).
Reye's Syndrome: Aspirin should not be used in children or teenagers for viral infections, with or without fever, because of the risk of Reye's syndrome with concomitant use of aspirin in certain viral illnesses.

EFFECTS ON LAB TEST RESULT:
May increase liver function test values. May decrease WBC and platelet count.

NURSING CONSIDERATIONS:
1. Aspirin should not be given to a child or teenager who has a fever, especially if the child also has flu symptoms or chicken pox. Aspirin can cause a serious and sometimes fatal condition called Reye's syndrome in children.
2. Stop using this medication and call your doctor at once if you have any symptoms of bleeding in your stomach or intestines. Symptoms include black, bloody, or tarry stools, and coughing up blood or vomit that looks like coffee grounds.
3. Take this medication with a full glass of water. Taking aspirin with food or milk can lessen stomach upset.
4. The enteric-coated pill has a special coating to protect your stomach. Breaking the pill could damage this coating. The extended-release tablet is specially made to release medicine slowly in the body. Breaking this pill would cause too much of the drug to be released at one time.
5. Avoid drinking alcohol while you are taking this medication. Alcohol may increase your risk of stomach bleeding.
6. Store aspirin at room temperature away from moisture and heat.
7. Tell patient who is allergic to tartrazine dye to avoid aspirin.
8. Advise client on a sodium-restricted diet that 1 tablet of buffered aspirin contains 553mg of sodium.