Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. CHAPTER 11 Analgesic Drugs 5/27/ Fall 2012

A DJUVANT D RUGS Assist primary drugs in relieving pain NSAIDs Antidepressants Anticonvulsants Corticosteroids Example: Adjuvant drugs for neuropathic pain Amitriptyline (antidepressant) Gabapentin or pregabalin (anticonvulsants) 5/27/ Fall 2012

W ORLD H EALTH O RGANIZATION A NALGESIC L ADDER 5/27/ Fall 2012

N ONOPIOID A NALGESICS : A CETAMINOPHEN Analgesic and antipyretic effects Little to no antiinflammatory effects Available over the counter and in combination products with opioids 5/27/ Fall 2012

M ECHANISM OF A CTION Similar to salicylates Blocks pain impulses peripherally by inhibiting prostaglandin synthesis 5/27/ Fall 2012

I NDICATIONS Mild to moderate pain Fever Alternative for those who cannot take aspirin products 5/27/ Fall 2012

T OXICITY AND M ANAGING O VERDOSE Even though available over the counter, lethal when overdosed Overdose, whether intentional or resulting from chronic unintentional misuse, causes hepatic necrosis: hepatotoxicity Long-term ingestion of large doses also causes nephropathy Recommended antidote: acetylcysteine regimen 5/27/ Fall 2012

D OSAGE Maximum daily dose for healthy adults is 3000 mg/day 2000 mg for elderly or those with liver disease Inadvertent excessive doses may occur when different combination drug products are taken together Be aware of the acetaminophen content of all medications taken by the patient (over-the-counter and prescription) 5/27/ Fall 2012

I NTERACTIONS Dangerous interactions may occur if taken with alcohol or other drugs that are hepatotoxic Should not be taken in the presence of Drug allergy L iver dysfunction Possible liver failure G-6-PD deficiency 5/27/ Fall 2012

H ERBAL P RODUCTS : F EVERFEW Related to the marigold family Antiinflammatory properties Used to treat migraine headaches, menstrual cramps, inflammation, and fever May cause GI distress, altered taste, muscle stiffness May interact with aspirin and other NSAIDs, and anticoagulants 5/27/ Fall 2012

A NALGESICS : N URSING I MPLICATIONS Before beginning therapy, perform a thorough history regarding allergies and use of other medications, including alcohol, health history, and medical history Obtain baseline vital signs and I&O Assess for potential contraindications and drug interactions 5/27/ Fall 2012

A NALGESICS : N URSING I MPLICATIONS ( CONT ’ D ) Perform a thorough pain assessment, including pain intensity and character, onset, location, description, precipitating and relieving factors, type, remedies, and other pain treatments Assessment of pain is now being considered a “fifth vital sign” Rate pain on a 0 to 10 or similar scale 5/27/ Fall 2012

A NALGESICS : N URSING I MPLICATIONS ( CONT ’ D ) Be sure to medicate patients before the pain becomes severe so as to provide adequate analgesia and pain control Pain management includes pharmacologic and nonpharmacologic approaches; be sure to include other interventions as indicated 5/27/ Fall 2012

A NALGESICS : N URSING I MPLICATIONS ( CONT ’ D ) Patients should not take other medications or over-the-counter preparations without checking with their physician Instruct patients to notify physician for signs of allergic reaction or adverse effects 5/27/ Fall 2012

M ONITOR FOR T HERAPEUTIC E FFECTS Decreased complaints of pain Decreased severity of pain Increased periods of comfort Improved activities of daily living, appetite, and sense of well-being Decreased fever (acetaminophen) 5/27/ Fall 2012