How Psychoactive Drugs Affect Us•Factors that determine effects andabuse potential include:•Route of administration•Speed of transit to the brain•Affinity for nerve cells andneurotransmitters
Routes of Drug Administration and Absorption.5 common ways that drugs enter the body
Routes of Drug Administration and Absorption.•Inhaling:•Allows the vaporized drugto enter the lungs, theheart and then the brain inabout 7-10 seconds (Mostrapid)(Pictures)• Marijuana inhaling tent used bythe Scythians, c. 500 B.C.• Man in India smokes ganja(marijuana) in a “chillum” pipe.
Routes of Drug Administration and Absorption.•Injecting:(Intravenous)•Puts drugs directly into avein(Intramuscular)•Put drugs into musclesor under skin
Routes of Drug Administration and Absorption•Snorting & MucosalExposure:• Drugs can be snorted andabsorbed throughcapillaries in the nasalpassages or placed onmucosal tissues in thegums, cheeks, or evenrectum and absorbed.•Cocaine snorter’s noseshowing how cocaineate a hole through thenasal septumseparating the nostrils.
Routes of Drug Administration and Absorption•Oral Ingestion:•Drug passes throughthe esophagus andstomach to the smallintestine where it isabsorbed by thecapillaries lining thewalls of the smallintestine.• Hindu ascetic preparesmarijuana for drinking.
Routes of Drug Administration and AbsorptionContact or TransdermalAbsorptionAbsorption through theskin is the slowestmethod of drug use. Itoften takes 1–2 days foreffects to begin and theabsorption can continuefor about 7 days.Nicotine, fentanyl, andheart medications canalso be absorbed thiswaySkin creams & ointmentsabsorbed through skin
Drug Distribution• Drugs Circulate through the bloodstream to the rest of the body where theycause an effect, be ignored, be absorbed or be biotransformed• Distribution depends on the drug itself and on blood volume of the person(6-8 quarts in an adult, 3-4 in child)• Takes 10 to 15 seconds after entering the bloodstream and has the greatesteffect on the brain and spinal cord
Drug Distribution: Blood-brain Barrier• The walls of the capillaries that forma protective shield around thenerves cells of the central nervoussystem (CNS) and guard againsttoxins, virus, and bacteria can bepenetrated by psychoactive drugs• Penetration happens becausepsychoactive drugs are Fat-soulableand the brain and its barrier are fatty• Psychoactive drugs such as heroin,nicotine, alcohol and marijuanacross this barrier more easily thanother substances.• Cocaine (water soluble) hitchhikesonto protein molecules to passthrough blood-brain barrier.• It takes 1–2 years for the blood-brain barrier to develop fully ininfants.
The Nervous System•Principle Target ofPsychoactive drugs•Network of 100 billionnerve cells & 100 trillionconnections•Nervous System is madeup of the:• Central Nervous System• Peripheral Nervous System(Somatic & Autonomic)PERIPHERALCENTRAL
Reward / Reinforcement Center•Part of the Brain thatencourages a person toremember and repeat anaction.•It is also affected by drugsand is thus responsible forcraving•Drugs act on the rewardpathway to trigger cravingfor euphoria or pain relief•AKA “mesolimbicdopaminergic rewardpathway”Reward System of the Brain
Neuroanatomy• Nerve cells: Consisting ofdendrites, the cell body, theaxon and terminals transmitimpulses by sendingneurochemicals AKA“neurotransmitters” across thesynaptic gap between thenerve cells or neurons• Messages travel in multipledirections but with purpose,enabling the senses totransmit messages to thebrain that, in turn, sendmessages and commandsback to the appropriatemuscles, tissues, and organs.A single nerve cell can receivesignals from hundreds, eventhousands of other nervecells.
Neuroanatomy•Neurotransmittersmove holding sacsin one nerve cell,across the synapticgap, slot intoreceptor sites,trigger an impulse,and then moveback to the sendingcell.Message Arrives
Neurotransmitters•The releasedneurotransmitters cross thesynaptic gap and slot intoreceptor sites on thepostsynaptic neuron, causingthe retransmission of themessage.•The slotted neurotransmittersare then released and eithermetabolized in the synapticgap or more likelyreabsorbed through reuptakeports in the sending terminal,ready to be transmittedagain.MessageTransmitted
Neurotransmitters & Receptors•Psychoactive drugs cannot createsensations or feelings that don’t have anatural counterpart in the body•So psychoactive drugs duplicate ormimic the natural counterpart in the bodyto a higher degree
If the cells senses too many neurotransmitters, then it closes downports.If there is too few neurotransmitters, then the cell opens more ports•Cocaine forces therelease of extraneurotransmitters,especially dopamine,epinephrine, andnorepinephrine.•It then also blocks thereuptake ports so theneurotransmitters cannotbe reabsorbed by thesending neuron thuscausing excessstimulation of the user.Cocaine forcesNeurotransmitterRelease
Heroin & Neurotransmitters• When heroin is taken, itslots into receptor sites onthe edge of the pain-transmitting nerve cell,causing a reduction in theamount of substance “P”that gets across the gap.• The heroin also slots intoreceptor sites on thereceiving neuron, blockingthe substance “P” thatgets through. Whenheroin or opioid use isdiscontinued, the painreturns unless that tissueor organ has beenrepaired.Heroin inhibitssubstance “p”pain message
Agonist & Antagonist•Drugs disrupt neutral messagetransmission•Agonist are those drugs that enhanceneutral signals mimic or facilitate theeffects of neurotransmitters•Antagonist are those drugs that blockneurotransmitters
252521Meth FacesPictures from www.anti-meth.org
262621Meth MouthUnlike other drugs or vices,methamphetamine seems to be taking aunique and horrific toll inside its usersmouths. In short stretches of time,sometimes just months, a perfectly healthyset of teeth can turn grayish-brown, twistand begin to fall out, and take on a textureless like that of hard enamel and more like apiece of ripened fruit.
28Skin and soft tissue infections are the mostfrequent cause of hospital admissions amongintravenous drug users.28Skin Abscesshttp://img525.imageshack.us/img525/3120/arm2if2.jpg http://vvoice.vo.llnwd.net/e14//the-scourge-of-skid-row.1705518.40.jpg
3131Necrotizing fasciitis. Sagittaloblique 3D VR CT imageobtained in a 35-year-old manwith a history of intravenous drugabuse and necrotizing fasciitis ofthe right upper extremity showsextensive débridement of theupper-extremity skin,subcutaneous tissues, andunderlying muscles. The patienthad undergone multipledébridements and a 6-week courseof intravenous antibiotics. Thearea showed eventual healing bysecondary intention, and a skingraft was not required.
3232Krokodil or "Crocodile" in Russian is a homemade substituteof heroin, which is casting deathly shadows over the lives ofthousands of Russias drug addicts. It has a reptilian namebecause the users skin starts developing crocodile-likeunpleasant scales, over repeated use. And that is arguably theleast this deadly drug can do to your body. The scales wouldgive way to decaying sores and gray skin. The flesh wouldsoon start to degenerate and would peel away leaving bonesexposed. The users literally rot to death.
3636Prescription drugs cantransform lives. For themillions of patients who takethem, prescription drugs bringdramatic improvements inhealth and quality of life. Butwhen abused or misused,many of these medicationscan have effects that disruptrather than improve lives.Some prescriptionmedications-particularlyopioids, central nervoussystem (CNS) depressants,and stimulants-alter thebrains activity, and misuse orabuse of these drugs can leadto compulsive drug seekingand use, the hallmark ofaddiction.
38Inhalants38Inhalants refers to the vapors from toxic substances whichare inhaled through the nose and/or mouth to reach a quickhigh. Of more than 1,000 household and other commonproducts that could be abused as inhalants, most oftenused are shoe polish, glue, toluene, gasoline, lighter fluid,nitrous oxide or “whippets,” spray paint, correction fluid,cleaning fluid, amyl nitrite or “poppers,” locker roomdeodorizers or “rush,” and lacquer thinner or other paintsolvents.Most of these produce effects similar to anesthetics, whichslow down the body’s functions. After an initial high andloss of inhibition comes drowsiness, light-headedness andagitation.