Drugs and Our Society How Drugs Work in the Body and the Mind

Pharmacology of Drugs 1.Pharmacology relates to the way drugs are: -administered to the body -how they are absorbed -how distributed through the body -how metabolized by the body -and how excreted from the body 2.There are 4 primary routes through which drugs are administered -oral / inhalation / injection / absorption

Administration of Drugs 3.Ingesting drugs (oral) produces different effects from inhaling -smoking marijuana has a different effect from ingesting it -chewed tobacco is absorbed differently from smoked tobacco -the effects of injected narcotics are more intense than other forms 4.Not all drugs can be injected, such as marijuana -resin and water don’t mix

Admin of Drugs, cont -it is less likely to be abused than narcotics and opiates -which can be injected 5.Cocaine is more likely to be abused than caffeine -the effects of cocaine are much more powerful -it takes effect more quickly. Depending on administration -injected more powerful than snorting

Admin of Drugs, cont 6.Alcohol is metabolized in the liver -primary absorption site is the small intestine -removed through exhaling / sweat / urination -rate of 3/4 th ounce per hour 7.Snort cocaine -mucous membranes in nose absorb drug quickly -effects are felt within minutes

Admin of Drugs, cont 8.Amphetamines taken orally -produce peak effects in 2 to 3 hours -eliminated in 2 to 3 days -effect of injected amphetamines is 5 minutes 9.Caffeine effects is between 15 to 45 minutes -metabolized in the liver -removed by the kidneys

Admin of Drugs, cont 10.Marijuana smoked allows half of the THC to be absorbed through lungs -before entering the bloodstream -the liver initially detoxifies the THC -it is removed primarily through feces

Oral Administration 1.Ingesting by mouth is the oldest and easiest way -digesting / then absorbing into the bloodstream 2.Absorption time is longer after ingestion -between 5 and 30 minutes -not complete until after 6 to 8 hours 3.Gastrointestinal system consists of the esophagus, stomach / intestines -enables body to absorb nutrients -and remove waste

Oral Administration, cont 4.Interior of stomach is highly acidic -drugs can be impacted by acidity -this can weaken effect of morphine / heroin / cocaine -which are highly alkaline drugs 5.From small intestine to bloodstream -drugs then processed by the liver -liver “metabolizes” the drug -enzymes break the drug down

Oral Administration, cont 6.A larger dosage is needed when taken orally drugs show increase in enzyme activity -Phenobarbital has effect and duration decreased -valium and marijuana the active metabolites produce similar effects to the parent drug and prolongs the effect considerably

Oral Administration, cont 8.Ingesting drugs on a full stomach or an empty stomach -does make a difference in the effect drugs will have on the body

Injection 1.Parenteral drug use refers to the injection of drugs -injected drugs reach the brain quickly -the fastest means of injection is intravenous (IV): within a vein -it is called “mainlining” -with prolonged use, the vein wall loses strength and elasticity -and the vein can collapse

Injection 2.Heroin injected into the forearm -10 to 15 seconds to the heart / lung / and brain -blood vessel walls are relatively insensitivity -irritating material can also be injected -it is possible to deliver high concentrations of a drug 3.Another method is intramuscular -which is injection into a muscle 4.Muscle tissue serves as a filter, so the absorption time is slower

Injection, cont 5.Example: -onset of euphoria after injecting heroin intravenously is 7 to 8 seconds -intramuscular the euphoric onset is 5 to 8 minutes -the more blood vessels the muscle has, the faster the absorption -deltoid muscle injections are faster than the buttocks

Injection, cont 6.Subcutaneous injection -injecting just below the layers of the skin -the drug is absorbed less evenly and slowly -it is also referred to as a “skin pop” or “skin popping”

Inhalation 1.This is where drugs are absorbed into the bloodstream via the lungs 2.Speed and efficiency are quite high -due to the accessibility of capillary walls -from the lungs, drugs go directly to the brain in 5 to 8 seconds -effects usually are brief 3.Smoking tobacco / marijuana / crack -‘huffing’ glue, paint, other inhalants

Absorption Through Skin or Membranes 1.Quick absorption - 15 to 20 seconds 2.Mucous membranes -found in the nose / mouth / rectal / and vaginal areas -drug adheres to membrane -dissolves into bloodstream 3.Intranasal -sniff / snort a drug such as cocaine -in dust or powder form

Absorption Through Skin or Membranes 4.Transdermal application -ointment applied to skin -patch placed directly on the skin

How Drugs Exit the Body 1.The body has a fairly efficient system to rid itself of unwanted substances -gases and solvent vapors can be eliminated in exhaled breath -small amounts can be eliminated through sweat / saliva / or feces -but primarily through urine 2.The major job of elimination is the liver and kidneys -the “dynamic duo” of excretion

Kidneys 1.Two organs about the size of a fist -located on either side of the spine 2.Primary functions: -maintain balance between water and salt in body fluids -and the excretion of excess water in the form of urine 3.It functions as a complex filtering system -the kidneys physically remove certain substances from the blood

Kidneys, cont 4.-it filters everything out -then selectively reabsorbs what is required 5.The kidney can make urine acidic or basic -the pH value can be manipulated -pH value refers to the acidity of a solution

Liver 1.A large organ located high in the stomach under the diaphragm 2.Function -compare it to a chemical factory -molecules are modified to form new useful substances -toxic molecules are changed into less harmful substances 3.Changes made by molecules are called ENZYMES -depending on the drug / liver can create additional enzymes

Liver, cont - metabolizes (breaks down) the molecules - the product of metabolism is metabolites, which are more useful and less toxic - they breakdown drugs into less active forms, called detoxification 4.Metabolites of certain drugs can be more active than the original (active metabolites) -good examples are THC and psilocybin

Rate of Excretion 1.Kidneys operate most efficiently with high concentrations of the drug in the blood 2.Concentration falls -kidneys cannot filter out the drug at the same rate 3.Rate of excretion can be described in terms of ‘half-life’ -time for the body to eliminate half -of a given blood level of drug

Rate of Excretion, cont 4.Half the original blood level is eliminated in 30 minutes -30 minutes later, level is 25% -30 minutes later, level is 12.5% 5.Every 30 minutes the body gets rid of half the drug circulating in the blood -so the half-life of the drug is 30 minutes 6.Half-life equals 1 hour -50% / 25% / 12.5% / 6.25% / etc.