Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. Chapter 6 Nonopiod (Nonnarcotic) Analgesics

Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. Nonopioid Analgesics  Pain is an unpleasant sensory or emotional experience arising from actual or potential tissue damage.  A person’s response to pain is based on their perception of pain.  Both perception and reaction to pain are often psychologically based. 2

Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. Salicylates  Acetylsalicylic acid (aspirin) is the most common salicylate used today.  Aspirin is the most useful salicylate for treating pain.  Aspirin works by inhibiting prostaglandin synthesis.  It primarily inhibits the enzyme cyclooxygenase (COX). 3

Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. Salicylates  Aspirin is rapidly and almost completely absorbed from the stomach and small intestine.  It reaches its peak effects in 30 minutes when taken on an empty stomach.  Buffered tablets reach their peak effect in 20 minutes.  Most aspirin is coated because it is irritating to the stomach.  Aspirin can be administered rectally.  Aspirin demonstrates zero-order kinetics. 4

Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. Salicylates  Pharmacologic Effects  Analgesic It is used to treat mild to moderate pain, including dental pain. It is used to treat mild to moderate pain, including dental pain.  Antipyretic Aspirin reduces fever because of its ability to inhibit prostaglandin synthesis in the hypothalamus. Aspirin reduces fever because of its ability to inhibit prostaglandin synthesis in the hypothalamus. Aspirin reduces fever by inducing peripheral vasodilation and sweating. Aspirin reduces fever by inducing peripheral vasodilation and sweating. 5

Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. Salicylates  Pharmacologic Effects  Antiinflammatory This effect is also from aspirin’s ability to block prostaglandin synthesis. This effect is also from aspirin’s ability to block prostaglandin synthesis. Aspirin reduces redness and swelling at the inflamed area. Aspirin reduces redness and swelling at the inflamed area.  Antiplatelet Aspirin irreversibly binds to platelets. Aspirin irreversibly binds to platelets. Aspirin inhibits both prostacyclin and thromboxane A2 depending on the dose used. This helps prevent blood from clotting. Aspirin inhibits both prostacyclin and thromboxane A2 depending on the dose used. This helps prevent blood from clotting. 6

Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. Salicylates  Adverse Reactions  Aspirin’s adverse reactions are many. These reactions have limited aspirin’s everyday use.  The many adverse reactions of aspirin include: Gastrointestinal – They are a direct result of direct gastric irritation and blockage of prostaglandins. Gastrointestinal – They are a direct result of direct gastric irritation and blockage of prostaglandins. Bleeding – Bleeding time is prolonged because of aspirin’s effects on platelets and prostaglandins. Bleeding – Bleeding time is prolonged because of aspirin’s effects on platelets and prostaglandins. 7

Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. Salicylates  Adverse Reactions  Reye syndrome  Hepatotoxicity  Renal toxicity  Hypersensitivity Patients with asthma are at a higher risk for hypersensitivity or allergic reactions. Patients with asthma are at a higher risk for hypersensitivity or allergic reactions. 8

Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. Salicylates 9

Salicylates  Uses  Mild to moderate pain  Fever  Inflammation  Prevention of stroke or heart attack  Antiplatelet effects 10

Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. Nonsteroidal Antiinflammatory Drugs (NSAIDs)  NSAIDs are among the most useful drugs available to treat dental pain.  Several of these drugs are available without a prescription.  As with aspirin, NSAIDs work by inhibiting the enzyme cyclooxygenase.  Most NSAIDs demonstrate peak effects within 1-2 hours.  Food reduces the rate but not the extent of NSAID absorption.  Pharmacologic effects are similar to aspirin and include analgesic, antipyretic, and antiinflammatory actions. 11

Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. NSAIDs  Adverse Reactions  As with aspirin, adverse reactions include gastrointestinal effects, renal effects, and hypersensitivity reactions.  NSAIDs can cause central nervous system effects including sedation, dizziness, confusion, depression, and headache.  NSAIDs reversibly inhibit platelet aggregation. This effect only remains as long as the drug is in the body. 12

Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. NSAIDs 13

Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. NSAIDs 14

Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. NSAIDs  Therapeutic Uses  Medical Osteoarthritis, rheumatoid arthritis, general pain and inflammation, fever, dysmenorrhea Osteoarthritis, rheumatoid arthritis, general pain and inflammation, fever, dysmenorrhea  Dental General dental pain and inflammation General dental pain and inflammation Often better than opioid analgesics Often better than opioid analgesics 15

Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. NSAIDs  Cyclooxygenase II (COX) Specific Agents  COX II is only synthesized when inflammation is present.  Blocking COX II receptors only should decrease the risk for adverse effects. Blocking COX I appears to be responsible for adverse effects.  These drugs were thought to be less irritating to the stomach.  However, these drugs can cause significant cardiovascular and gastrointestinal toxicity.  They offer no advantage over nonselective NSAIDs. 16

Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. Acetaminophen  Acetaminophen is not related to salicylates or NSAIDs.  It is rapidly and completely absorbed from the gastrointestinal tract.  It achieves peak levels in 1-3 hours.  Acetaminophen is metabolized by the liver.  If large doses are ingested, an intermediate metabolite, N-acetyl-p-benzoquinonamine is formed. This metabolite is toxic. 17

Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. Acetaminophen  Acetaminophen has both analgesic and antipyretic effects.  Therapeutic doses have no effect on the cardiovascular and respiratory system.  It does not have any real gastrointestinal effects. 18

Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. Acetaminophen  Adverse Effects  Hepatotoxicity Can occur after the ingestion of a single toxic dose (20-25 gm) or after long term use of therapeutic doses. Can occur after the ingestion of a single toxic dose (20-25 gm) or after long term use of therapeutic doses. Children are at high risk for hepatotoxicity because they are often given doses that are not age- and weight-appropriate. Children are at high risk for hepatotoxicity because they are often given doses that are not age- and weight-appropriate. Signs and symptoms include nausea, vomiting, abdominal pain, anorexia. Signs and symptoms include nausea, vomiting, abdominal pain, anorexia.  Nephrotoxicity It has been associated with long-term use. It has been associated with long-term use. 19

Mosby items and derived items © 2007 by Mosby, Inc., an affiliate of Elsevier Inc. Acetaminophen  Chronic large doses of alcohol can increase the risk for hepatotoxicity.  Acetaminophen is used for its analgesic and antipyretic effects.  It is useful in patients with aspirin or NSAID hypersensitivity.  It is useful for children because it is not known to cause Reye syndrome. 20