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Drugs and Our Society The Physiological Impact of Drugs Part 5 1. 2. How drugs impact the physical aspects of the body Timing - how often drugs are taken - once a drug is taken there is a latency period Concentration of the drug is increasing in the blood - but not high enough to feel effects of drug - many times you can feel the drug sensation building - you may feel warm / your skin is tingling / your head feels as if it is expanding How long is this latency period? 1. 2. 3. 4. It depends on the absorption time of the drug - as concentration of the drug continues to rise - effects become stronger Even when maximum effect is reached - concentration can continue to rise Alcohol: - drink and visit - feel giddy and uninhibited - you are becoming intoxicated Maximum effect is reached when you pass out - concentration continues to rise = death latency period, cont 5. 6. Timing is important - whether a prescription drug or an illicit drug Both can result in a toxic effect - either an overdose or death Drug Interactions This refers to the effects of two or more substances - also called a ‘polydrug’ - they can be additive / antagonistic / or synergistic - 25 % of emergency room admissions are for alcohol + medications 2. Additive effect - combination of drugs are purely additive - one a value of 4 / other a 6 / additive effect equals 10 - aspirin + pain reliever have a greater effect 1. Antagonistic Effect 1. 2. 3. Effect of one drug is diminished or negated when combined with another One has a value of 6 / second value of a 4 - effective value of a 3 - drug has been diminished - Valium and Librium diminish the value of oral contraceptives Using the antibiotic tetracycline with milk or antacids - negates the antibiotic Synergistic Effect 1. 2. 3. The total effect is greater than the sum of their individual effects The action of two or more agents - synergism: enhanced / unpredictable effect - caused by combining two or more substances - such as barbiturates and alcohol Hyperadditive effect - produce greater effect than administered separately Synergistic Effect, cont 3. 4. - one drug may double or even triple the effect of another Potentiation - one drug will have no effect - unless taken with another drug One drug with no effect - combined with a drug value of 6 - potentiation effect equals a 10 Factors influencing the effects of drugs 1. Age - infants and elderly are more sensitive to drug effects - elderly makeup 12% of the population but take between 1/4th and 1/3rd of all prescription drugs - 2 of every 3 senior citizens aged 65 and older take one or more daily - tolerance for alcohol lessens as you age - BAC’s are higher / less bodily fluids Factors, cont 2. - as people age, the percent of body fat increases - some drugs accumulate in adipose tissue - this increases sensitivity to those drugs and a toxic reaction can occur Gender - females and males respond differently to drugs - the differences are related to water and body fat Factors, cont - - women who weigh the same as men have higher percentage of body fat and a lower percentage of water this makes women more sensitive to drugs fat stores drugs water dilutes the amount of drug in the bloodstream hormones also make a difference PMS / pregnancy Factors, cont 3. 4. Dosage - already discussed the ED and LD - the smallest amount of a drug required to produce the desired effect - is called the “threshold dose” Purity and potency - purity: the quality of a substance / the state of non-contamination of a drug - potency: ability to produce an effect relative to other drugs (the less needed to produce a response, the more potent the drug) Factors, cont 5. 6. Many health problems that users experience are due to the purity of a drug - the quality varies greatly in illicit drugs - it becomes a significant factor in the drug’s effect A DEA report on heroin: - purchased in the mid-1970’s: 6% purity - early 1980’s: less than 4% purity - early 1990’s: more than 20% purity - today: it ranges from 20% to 90% depending on the location Factors, cont 7. 8. Potency - looking at heroin / morphine / and aspirin as pain relievers (?) - heroin is the most potent - next is morphine - and then aspirin - so a smaller amount of heroin is needed to reduce the same pain Some drugs vary naturally in potency - percentage of THC ranges from 1% to 10%