Drug Schedules • Goal: to organize the control of drugs under 5 classifications (schedules of controlled substances) • Potential for abuse • Accepted medical use • Schedule 1: High potential for abuse; no accepted medical use (LSD) • Schedule II: High potential for abuse; Some accepted medical use (cocaine) • Schedule III: Some potential for abuse; accepted medical use (mixtures-1.8%codeine) • Schedule IV: Low potential for abuse; accepted medical use (valium) • Schedule V: Minimal abuse potential; widespread medical use (laxatives)
Toxicity: • -Poisonous, deadly, or dangerous • -Effects of drugs that interfere with normal functioning • Acute Effects: result from a single administration of a drug; the drug is present in the system • Chronic Effects: Result from long-term exposure • Onset of action; duration of the effect: • The faster the onset (when a person starts to feel the effects) & the shorter the duration (effect of drug lasts a short period), the more likely the person will become physically dependent on the drug (depressants). • In other words, the faster the absorption, the more intense the high; but the faster the absorption, the shorter the duration.
Physical dependence: When a person begins to experience withdrawal symptoms after the drug is taken away. Bodies need to constantly have the drug or drugs. • Physical dependence depends on: • -how quickly the drug enter the brain • -how quickly the drug leaves the system • Intense physical dependence: • Barbiturates (grouped on the basis of the duration of their activity) • Short acting- (15 min. onset; 2-3 hour duration) most likely to be abused. • Intermediate acting (30 min. onset; 5-6 hour duration) • Long-acting (1 hour onset; 6-10 hour duration)
Psychological dependence is the mental inability to stop using the drug. • Some Facts: • *Alcohol (most widely used depressant) • *Narcotics (heroin)-b/c most potent • & other CNS depressants • *Sedatives are most widely prescribed depressant. • Potency of Opiates: • Potency-amount of drug necessary to cause an effect. The smaller the dose required to achieve a drug action, the greater the potency. • *Morphine is 10X stronger than raw opium. • *Heroin is 3X as potent as morphine (accounts for 95% of all recreational narcotic use in U.S.)
Other Factors that Determine Drug Effects • Non-specific Effects: The effect of the drug does not depend solely on chemical interactions • Influences of expectancy, experience, & setting can also help determine the drug’s effect. • Weight, Age, & health status also influence the effects a drug will have. • When 2 or more drugs are taken together, their interaction can alter the effects of the drugs, counteract the effects of one or more of the drugs, or increase the effects.
Dose-response Relationship: The size of the effect changes directly with the drug dose • *Increasing the dose of the drug will not always increase the magnitude of the effect. • Time-Dependent Factors in Drug Actions: • -How the drug was administered • -How rapidly it was absorbed • -How it is eliminated from the body
Methods of Administration: To produce an effect, a drug has to enter the body. • 1. Orally: By mouth; the most common way of taking a drug is by swallowing it. • Advantages: • Easy to use • Painless • Disadvantages: • Complicated way to enter bloodstream • Deactivated by food/bile • Metabolized by liver
2. Injection-IV: Some drugs are injected using a syringe & needle. A drug that is injected goes directly under the skin into a blood vessel. Drugs must be in liquid form to be injected into the body. • Advantages: • Directly into blood • Rapid results • Deliver high concentration • Irritating material can be administered • Disadvantages: • Vein walls lose strength • Introduce infection & disease • Needle phobia
3. Injection-intramuscular: Injected using a syringe & needle, into the muscle • Advantages: • Rapid absorption • Large volume of drug • Disadvantages: • Tissue irritation • Pain (for some) • Needle phobia
4. Inhalation: Some drugs are inhaled through the nose or mouth and enter the bloodstream through the lungs. • Advantages: • Very rapid absorption (5-8 seconds) • Very accessible to lungs • Disadvantages: • Irritate mucous membranes of lungs • Dosage difficult to control
5. Topical: A drug that is absorbed enters the bloodstream through the skin or mucous membranes. Ointments, creams, lotions, sprays, & patches contain drugs that are absorbed. (cocaine) • Advantages: • Slow, steady absorption • Disadvantages: • Not absorbed well thru skin • *Some drugs are also implanted, or placed under the skin where they can be released into the bloodstream. For example, some forms of cancer therapy involve implanting drugs under the skin