Mastering Analgesics

Key Points on Analgesics and Their Therapeutic Effects

• Aspirin is an analgesic that works by inhibiting cyclooxygenase 1 & 2, which inhibits prostaglandin synthesis and prevents inflammation.
• Aspirin is also anti-inflammatory, antipyretic, and affects bleeding time by inhibiting platelet aggregation.
• Toxic effects of aspirin include GI bleeding, tinnitus, nausea, vomiting, metabolic acidosis, decreased uric acid absorption, salicylism, delirium, and hyperventilation.
• Corticosteroids, produced in the adrenal cortex, inhibit phospholipase A2 and arachidonic acid synthesis, resulting in analgesic and anti-inflammatory effects.
• Side effects of corticosteroids include gastric ulcers, immunosuppression, osteoporosis, hyperglycemia, redistribution of body fat, and acute adrenal insufficiency.
• Narcotics, also known as opioids, are mu opioid receptor agonists that provide analgesic effects by agonizing receptors in the CNS.
• Common narcotics include morphine, hydrocodone, oxycodone, codeine, heroin, and Demerol.
• Combination narcotics, such as Vicodin and Percocet, contain a narcotic and acetaminophen (APAP) for more severe pain management.
• Therapeutic effects of morphine include meiosis, sedation, analgesia, respiratory depression, pneumonia, hypotension, urinary retention, constipation, nausea, vomiting, and euphoria or dysphoria.
• Overdose of morphine can lead to respiratory depression, meiosis, and coma.
• Drugs like naloxone, naltraxone, methadone, and buprenorphine are used to treat overdose and addiction to narcotics.
• Nitrous oxide is an inhalation agent that provides mild analgesic effects and is commonly known as laughing gas.
• Side effects of nitrous oxide include tingling, nausea, and long-term exposure can cause peripheral neuropathy.

Overview of Analgesics: NSAIDs and Acetaminophen

• Analgesics are drugs that relieve pain and can also have anti-inflammatory effects.
• NSAIDs (non-steroidal anti-inflammatory drugs) are a category of analgesics that limit or prevent inflammation.
• Aspirin, also known as acetyl salicylic acid (ASA), is a non-selective COX-1 and COX-2 blocker and is irreversible.
• Aspirin can cause negative effects on the gastrointestinal (GI) system, such as an upset stomach.
• Ibuprofen (Motrin, Advil) is a reversible COX-1 and COX-2 blocker and can be tough on the kidneys.
• Naproxen (Aleve) is another NSAID and has a longer half-life than other NSAIDs.
• Ketorolac is available in intravenous, intramuscular, and oral forms.
• Indomethacin has been linked to rare cases of blood disorders.
• Phenylbutazone (Bute) is used for animals.
• Celecoxib and meloxicam are newer drugs that selectively block COX-2 and are commonly prescribed for arthritis and chronic pain.
• Acetaminophen (Tylenol) is not an NSAID and its exact mechanism is not fully understood.
• Acetaminophen can be hepatotoxic in higher doses and can interact negatively with alcohol, impacting the liver.