OPIOIDS I. Where do they come from? – poppy plant: from middle east and Asia – dried sap from plant is opium; cultivated annually BUT plant produces drug within only 10 day window 87% of world’s opium comes from Afghanistan (2005 U.N. report) – major active ingredient in opium: morphine / synthesized in 1803 / named after the Greek god of dreams Morpheus / morphine altered in late 1800s into heroin-a “heroic” TX (3-10x as strong as morphine) / Fentanyl OPIOIDS II. Medical Uses – As pain reliever (morphine, demerol, codeine, lortab, lorcet, percodan, percocet, vicodin, oxycontin) – with chronic pain or terminal patients – in some cough suppressants – treatment of diarrhea, which is dehydrating OPIOIDS III. Prevalence 1998: heroin + non-medical use of analgesics – Lifetime- 6.4% 2001: H: 1.4% P: 9.8% Past Year- 2% 0.2% 3.7% Current- .9% 0.1% 1.6% • current users: # significantly increasing it was estimated that there were 141,000 new users of heroin in 1995 - rate of new heroin users increasing; 90% are under age 26 and smoke, sniff or snort it rather than inject……stigma? - DAWN data: 14% of all drug-related episodes involve heroin OPIOIDS IV. Mechanisms of action • opiates trigger our own brain chemicals, the endorphins (short for “endogenous morphine”) to relieve pain • naloxone reverses and blocks effects of opiates by blocking opiate receptor sites OPIOIDS V. Effects • produces short-lived euphoria, profound relaxation, body warmth (lowers body temp) • tolerance develops rapidly to opiates so increasing doses is very common • drug taking becomes a chore to avoid withdrawal SX - illustrates ? reinforcement Rats: heroin tolerant Received injection of heroin 15 mg/kg in familiar environment Overdose rate: 32% Rats: heroin tolerant Received injection of heroin 15 mg/kg in unfamiliar environment Overdose rate: 64% Received injection of heroin 15 mg/kg for first time Overdose rate: 96% Control rats: No heroin tolerance To some degree, drug tolerance is associated with environmental factors. Tolerance may disappear or decrease if a drug is used in an unfamiliar environment. A diagram of Siegel’s rat experiment OPIOID WITHDRAWAL • Stoppage (or reduction] in opioid use that has been heavy and prolonged (several weeks +) • OR administration of opioid antagonist after period of use • Symptoms include: (need at least 3 for DSM criteria) – – – – – – dysphoric mood diarrhea muscle aches insomnia nausea or vomiting runny eyes or nose - yawning - fever - dilation of pupils, piloerection or sweating OPIOIDS VI. Treatment - methadone TX: peak concentration occurs 2-4 hours after taken, in contrast to effects of other opiates which kick in right away like a hammerblow; metabolites of methadone are inactive, unlike other narcotics - blood levels of methadone, when given orally, is below ED level in tolerant patients, and is safely above the threshold for withdrawal...so, methadone combines safety and long action - LAAM, naltrexone, buprenorphine - TCs OPIOIDS • Needle exchange programs to prevent HIV: are you pro/con? • Should heroin be given to terminal patients? Do terminal patients have right to die with drugs? • Should non-terminal pain patients be freely medicated with morphine or even stronger painkillers? OPIOIDS • Morphine treatment for pain generally given to 2 groups of patients: – post-surgery patients receive it on short-term basis – cancer and burn victims given it for much longer durations (typically given IM or under the skin) What about potential for addiction?