1. Drugs and Our Society The Physiological Impact of Drugs Part 5

2. How drugs impact the physical aspects of the body 1. Timing -how often drugs are taken -once a drug is taken there is a latency period 2. 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

3. How long is this latency period? 1. It depends on the absorption time of the drug -as concentration of the drug continues to rise -effects become stronger 2. Even when maximum effect is reached -concentration can continue to rise 3. Alcohol: -drink and visit -feel giddy and uninhibited -you are becoming intoxicated 4. Maximum effect is reached when you pass out -concentration continues to rise = death

4. latency period, cont 5. Timing is important -whether a prescription drug or an illicit drug 6. Both can result in a toxic effect -either an overdose or death

5. Drug Interactions 1. 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

6. Antagonistic Effect 1. Effect of one drug is diminished or negated when combined with another 2. 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 3. Using the antibiotic tetracycline with milk or antacids -negates the antibiotic

7. Synergistic Effect 1. The total effect is greater than the sum of their individual effects 2. The action of two or more agents -synergism: enhanced / unpredictable effect -caused by combining two or more substances -such as barbiturates and alcohol 3. Hyperadditive effect -produce greater effect than administered separately

8. Synergistic Effect, cont -one drug may double or even triple the effect of another 3. Potentiation -one drug will have no effect -unless taken with another drug 4. One drug with no effect -combined with a drug value of 6 -potentiation effect equals a 10

9. 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 1/4 th and 1/3 rd 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

10. Factors, cont -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 2. Gender -females and males respond differently to drugs -the differences are related to water and body fat

11. 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

12. Factors, cont 3. Dosage -already discussed the ED and LD -the smallest amount of a drug required to produce the desired effect -is called the “threshold dose” 4. 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)

13. Factors, cont 5. 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 6. 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

14. Factors, cont 7. 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 8. Some drugs vary naturally in potency -percentage of THC ranges from 1% to 10%