Exam 3- Analgesics, Antipyretics, and Anti-inflammatory Agents Flashcards
Opioid analgesics
Include full agonists, partial agonists, and antagonists
•Morphine – prototypical opioid agonist
–Pure alkaloid of morphine isolated in 1803
–Named after Morpheus, the Greek god of dreams
•Three types of opioid receptors
–Mu (µ) – Morphine – major analgesic receptor
–Delta (∆) – Spinal analgesia
–Kappa (K) – Morphine and other high potency analgesics
Opioid pharmacodynamics
Most opioid analgesics act at the µ receptor in brain and spinal cord
–Side effects – euphoria, respiratory depression, physical dependence
–These drugs are regulated under the Controlled Substances Act and policed by the DEA
Opioid pharmacokinetics
Oral forms have slower onset of action, delayed peak times and longer duration of action than drugs administered parenterally
–Onset of action – varies from 2 – 60 minutes
–Half-life – generally up to 6 hours
–Metabolized in liver and excreted in urine
Agonists
Codeine – Tylenol #3
–Hydrocodone – Vicodin, Lortab
–Oxycodone – Percocet, Oxycontin
Mixed agonist-antagonists
activate one type of opioid receptor while blocking another type
–Produce fewer side effects than true opioids
–Often used for analgesia during labor, and as anesthesia before surgery
•Butorphanol (Stadol)
•Nalbuphine (Nubain)
Tramadol (Ultram)
Centrally-acting, non-opioid drug
–Binds to µ receptors
–Used for mild to moderately severe pain
–Biotransformed by CYP2D6 in the liver
–Poses little risk for tolerance and abuse
–Respiratory depression occurs with overdose and alcohol consumption
Adverse effects: •CNS •GI •Respiratory •Drug tolerance and dependency
NSAIDS
•Two types
–Non-selective COX inhibitors
–COX-2 inhibitors
•Indications – exert analgesic, antipyretic, and anti-inflammatory effects
–Ibuprofen, Naproxen, Aspirin, Toradol, Mobic
•Pharmacokinetics – as a group, NSAIDS exhibit high oral absorption, bioavailability, and protein binding
–Metabolized by liver and excreted by kidney
NSAID drug interactions
Highly protein bound
–Warfarin, digoxin, sulfa
•Special precautions when combining aspirin with other drugs
Acetaminophen
Tylenol – nonopioid, non-NSAID analgesic •Used in treatment of mild pain and fever •No antiinflammatory properties •Pharmacodynamics –PG and COX inhibition in the CNS •Pharmacokinetics –Well absorbed orally –Toxic to liver in large doses, hepatic and renal disease, alcohol abuse and malnutrition –2 grams is now maximum daily dose •Several drug interactions
Methotrexate
-folic acid antagonist
–Results in inhibition of DNA synthesis and cell reproduction → slows disease progression
•Small doses absorbed orally and widely distributed
•Adverse effects – hepatotoxicity, leukopenia, anemia
•Many drug interactions
•Patient education
Allopurinol (Zyloprim)
prevents formation of uric acid by inhibiting xanthine oxidase
Colchicine
decreases inflammation by decreasing movement of leukocytes into tissues containing urate cyrstals (no analgesic or antipyretic effects)
Probenecid (Benemid)
increases urinary excretion of uric acid
Sulfinpyrazone (Anturane)
similar to probenecid and used for chronic gout
What are the black box warnings on NSAIDS?
the potential for increased risk of cardiovascular (CV) events and the well described, serious, potentially life-threatening gastrointestinal (GI) bleeding associated with their use.
What are the recommendations in the treatment of pain?
nonopioid analgesia is the primary choice for management, especially if inflammation accompanies or is the cause of the pain. Although any NSAID may be used for this indication, several have been routinely used and proved effective. Ibuprofen is the most commonly used because it is inexpensive, available OTC, and short-acting so that acute pain can be managed without long-term effects and adverse reactions. Taking the drug around the clock, rather than as necessary, is most effective. Choice is based on adverse reactions, cost, duration of action, and patient preference. Health-care providers often choose one short-acting drug (ibuprofen, diclofenac, ketoprofen, ketorolac, meclofenamate), an intermediate-acting one (naproxen), and a longacting drug (ketoprofen ER) and use the same drugs repeatedly. Because different patients seem to respond better to different NSAIDs, if one drug does not produce the desired effect, another one can be tried. Acetaminophen is useful in treating mild to moderate pain that is not accompanied by or caused by inflammation. It is not intended for pain management for more than 5 days in children or 10 days in adults because of the increased risk for hepatic adverse reactions. For adults, a dose of 325 to 650 mg every 4 to 6 hours usually suffices. Children’s doses are based on weight: 10 to 15 mg/kg per dose every 4 to 6 hours. After age 14 years, the adult dose is used.
