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Pharmacology. CHAPTER 5. WHAT ARE AUTACOIDS?. OCCUR NATURALLY IN THE BODY. produced in one organ and are transported via the lymph system All occur (made) naturally in the body. Terms & Definitions. Autacoids - Examples:
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Pharmacology CHAPTER 5
OCCUR NATURALLY IN THE BODY produced in one organ and are transported via the lymph system All occur (made) naturally in the body.
Terms & Definitions • Autacoids - Examples: • Prostaglandins – lipids that are synthesized locally by inflammatory stimuli –↑↑PAIN receptors • Thromboxanes(a vasoconstrictor and a potent hypertensive agent, and facilitates platelet aggregation [clotting]). • Leukotrienes(Inflammatory molecules; precursor of prostaglandins) • “-kinins”- messengers
‘’FAKE’ DRUGS For some people, pain can also be effectively treated with inactive pills (placebos)
NON-OPIODS Non opioid analgesics are also called: nonnarcotic, peripheral, mild, and Antipyretic (agents that reduce fever) Opioid analgesics are also called: narcotic, central, or strong analgesics.
Classification of Analgesic Agents 2. Opioids (narcotics) Act primarily within the: central nervous system Depress the central nervous system Effective for severepain Examples: Morphine, Codeine, Agents in cough suppressants We will discuss this area more in the next chapter Difference is in their site of action Difference in their mode of action • Nonopioids (nonnarcotics) • Act primarily at the: peripheral nerve endings • Inhibit prostaglandin synthesis (regulating the contraction and relaxation of smooth muscle tissue) • Not effective for severe pain • 3 subgroups: • Salicylates (aspirin-like group) • NSAIDs • Acetaminophen
SALICYLATES ASPIRIN is the most useful and common salicylate to reduce pain (analgesic action) acetyl salicylic acid (ASA) – THE CHEMICAL NAME FOR ASPIRIN
Salicylates • Aspirin belongs to a class of medications called nonsteroidal antiinflammatory drugs (NSAIDs). • Aspirin and other NSAIDs, for example, ibuprofen (eg. Motrin, Advil) and naproxen (eg. Aleve), are widely used to treat fever (antipyretic action), pain (analgesic action), and inflammatory (anti-inflammatory action) conditions such as arthritis • Aspirin is also known for its anti-platelet action
Salicylates: ASA MECHANISM OF ACTION • Aspirinhave: • anti-inflammatory, • antipyretic, • analgesic, and • antiplatelet actions. • These actions are related to the ability to inhibit prostaglandin synthesis Whereas, Acetaminophendrugs have only antipyretic & analgesicactions.
Salicylates: ASA MECHANISM OF ACTION • Aspirin inhibits cyclo-oxy-genase (COX) to block production of prostaglandins • Prostaglandins can sensitize pain receptors to substances such as BRADYKININ(SEE NOTE) • A reduction in prostaglandins results in a reduction in pain
30 MINUTES REMEMBER NOT TO APPLY TOPICALLY TO ORAL MUCOSA!!!!
Salicylates: ASA ADVERSE REACTIONS • Reye’s Syndrome • Associated with use of aspirin in children & adolescents who took it when they had the chickenpox or influenza • Fatal disease that causes numerous detrimental effects to many organs, especially the brain and liver. • ACETAMINOPHEN and NSAIDs are now used for fever (antipyretic action) or pain (analgesic action) in pediatric and adolescents to reduce the chances of Reye’s Syndrome
WARFARIN A drug interaction between aspirin and Warfarin can result in significant bleeding
NSAIDs • A rapidly growing group with important application in dentistry • Mechanism of action and many of their pharmacologic effects and adverse reactions resemble aspirin • Many authors agree that the NSAIDs are the most useful drug group for the treatment of dental pain. • Most are available without a prescription.
NSAIDs PHARMACOKINETICS • Most NSAIDs peak in about 1-2 hours • Well absorbed orally and food reduces the rate but not the extent of absorption • Metabolized in liver, excreted in kidneys
NSAIDs PHARMACOLOGIC EFFECTS • have a significant anti-inflammatory effect • Similar as aspirin: • analgesic • antipyretic • anti-inflammatory • They inhibit prostaglandin synthesis
NO! NSAIDs are not addicting, tolerance does NOT develop, and no withdrawal syndrome can be induced.
NSAIDs ADVERSE REACTIONS 7. Pregnancy and Nursing • Contraindicated in pregnancy; • Like aspirin, NSAIDs given late in pregnancy can prolong gestation • IBUPROFENis drug of choice for nursing
400MG In usual prescription doses, NSAIDs can be shown to be statistically significantly better than codeine alone, aspirin, acetaminophen, or placebo.
NSAIDs CONTRAINDICATIONS & CAUTIONS • NSAIDs should be used with caution in patients with: • asthma • cardiovascular disease • Renal diseases with fluid retention • coagulation problems • peptic ulcer disease • ulcerative colitis Contraindicated in pregnancy
Acetaminophen • Used as an analgesic and antipyretic in children and adults when aspirin is contraindicated • Has no anti-inflammatory action
Acetaminophen PHARMACOKINETICS • Rapidly and completely absorbed from the GI tract • Peak plasma level in 1 – 3 hours • Half life of 1 to 4 hours • Metabolized by the liver • Excreted by the kidneys in 24 hours • When large doses are ingested, an intermediate metabolite is produced that is thought to be hepatotoxic and possibly nephrotoxic. .
Acetaminophen USES • Acetaminophen is used as an: • Analgesic agent (↓ pain) • Antipyretic agent (↓ fever)
Acetaminophen USES • Used when hypersensitivity to aspirin or for patients experiencing aspirin-gastric induced irritation. • Used as an antipyretic instead of aspirin for young children; due to aspirin’s association with Reye’s syndrome. • Can be used in all stages of pregnancy (always ask doctor)
Drugs Used to Treat Gout Allopurinol (Zyloprim) • used in PREVENTION of a gout attack. • Inhibits the synthesis of uric acid • Also used in patients receiving either chemotherapy or irradiation • If a pruritic rash should occur, the drug should be promptly discontinued Probenecid (Benemid) • used in PREVENTIONof a gout attack. • Is an uricosuric drug that increases uric acid excretion in the urine
MODERATE TO SEVERE PAIN At first referred to drugs that are derivatives of opium poppy Opioid or narcotic analgesics are used to manage dental pain in patients in whom NSAIDs are contraindicated