Sedative-Hypnotic Drugs and Alcohol CHAPTER 12 Sedative-Hypnotic Drugs and Alcohol

Sedatives and Hypnotics Sedatives are drugs used to induce a mild state of CNS depression characterized by both mental and physical calmness Hypnotics are drugs used to induce and maintain sleep The same drugs are used to induce both sedation and hypnosis; however, the dosage for inducing sedation is lower

Classification of Sedative- Hypnotic Drugs Barbiturates – a drug family of chemically similar drugs with similar actions and features Benzodiazepines – a drug family of chemically similar drugs with similar actions and features Miscellaneous nonbarbiturates – a group of drugs with dissimilar chemical structures and pharmacologic features

Pharmacology of Barbiturates Drugs classified as short, intermediate, and long-acting sedative-hypnotics At low doses they increase the inhibitory effects of GABA At high doses they act like general anesthetics, and can cause profound CNS depression and death in overdosage Barbiturates are also anticonvulsants

Barbiturates to Know Phenobarbital (Luminal) – long acting (6-12 hr) “hangover” – often used for epilepsy Pentobarbital (Nembutal) – intermediate (4-6 hr) Secobarbital (Seconal) – short (2-4 hr) help falling asleep

Effects of Barbiturates on the Sleep Cycle Decrease stage 1, falling asleep Increase stage 2, a lighter stage of sleep Decrease stages 3 and 4 referred to as deep sleep or slow-wave sleep Decrease REM sleep, and may cause REM rebound

Adverse Features of Barbiturates Cause drug tolerance with chronic use and drug dependency with abuse Can cause a severe type of physical drug addiction when chronically abused The withdrawal reaction from barbiturates can be serious, resulting in convulsions and death Drug interactions, induce microsomal enzymes to increase the rate of drug metabolism of all drugs metabolized by the microsomal enzymes

Reasons for decreasing use Enzyme induction tolerance,  DMMS Confusion in elderly Automatism REM rebound effect – nightmares Dangerous with alcohol

Pharmacology of Benzodiazepines Drugs classified as short, intermediate, and long-acting sedative-hypnotics Drugs also produce antianxiety, skeletal muscle relaxing, and anticonvulsant effects Act by increasing the inhibitory effects of GABA Drugs do not induce the drug metabolizing microsomal enzymes

Effect of Benzodiazepines on the Sleep Cycle Decrease stage 1, falling asleep Increase stage 2 Decrease stages 3 and 4 Do not significantly decrease REM sleep Benzodiazepines are considered safer drugs than the barbiturates, especially in overdosage

Benzodiazopines to Know Most frequent sleeping pill in hospital Flurazepam (Dalmane) – long acting (1-2 days) Temazepam (Restoril) – intermediate (8-10 hr) Triazolam (Halcion) short Decrease restfull sleep (stage3-4) not REM – Does not induce DMMS

Miscellaneous Nonbarbiturates Zolpidem and zaleplon are short-acting hypnotics that do not disrupt the sleep cycle These drugs increase the inhibitory effects of GABA but differently than other drugs Both drugs are considered to be safer than other hypnotics and are at low risk for abuse Side effects include dizziness, headache, GI disturbances, and mental confusion

To Know Zolpidem (Ambien) short acting (2-3 hr) doesn’t alter stage 3-4 or REM Zaleplon (Sonata) similar to Ambien

Alcohol Classified as a CNS depressant drug Unlike other drugs, alcohol provides nutritional calories Like other drugs of abuse, alcohol causes development of drug tolerance, dependency, and withdrawal reactions Most of the pharmacology of alcohol centers around its chronic use, abuse, and toxicology

Alcohol Metabolized at a constant rate Toxic effect: 10-15 cc alcohol = oz vodka = beer = glass wine Toxic effect: Low dose = carbohydrate High dose or with Tylenol = Toxic

Disulfiram (Antibuse) Used to treat alcoholism and deter drinking Disulfiram inhibits metabolism of alcohol, allowing acetaldehyde to accumulate Increased acetaldehyde produces severe nausea, vomiting, headache, and hypotension Alcoholics take the drug on a daily basis, knowing that if they drink any alcohol they will become violently ill