Substance Use & Abuse Ch.6

Most common form of depressant

alcohol

Types of CNS depressants

1. Benzodiazepines: Valium-Type Drugs: prescribed for anxiety, relaxation and sleep; treatment of neurosis, relaxation of muscles, alleviation of lower-back pain, treatment of convulsive disorders etc. - affect neurons that have receptors for the neurotransmitter GABA - distinguished primarily by their duration of action: short-acting (hypnotics), long-acting (sedatives 2. GABA: most common inhibitory transmitter in brain regions - limbic system (alter mood) - RAS (cause drowsiness) - motor cortex (relax muscles) 3. Barbiturates played an important historical role as sedative-hypnotic agents - 1st developed in 1903 - however, due to their narrow margin of safety and their abuse liability, they were replaced by benzodiazepines - caused many negative side effects, from nausea to death, from respiratory or cardiovascular depression

The effects of CNS

1. CNS depressants reduce CNS activity and diminish the brain's level of awareness. 2. depressant drugs include: - Benzodiazepines - Barbiturate-like drugs - Alcohol - Antihistamines - Opioid narcotics like heroin 3. depressants are usually classified according to the degree of their medical effects on the body. For example: - sedatives cause mild depression and relaxation -- anxiolytic—drugs that relieve anxiety - hypnotics induce drowsiness and encourage sleep -- amnesiac effects can cause the loss of memory 4. the same drug can cause different effects depending on dose - low dose (sedatives—relieve anxiety and promote relaxation) - higher doses (hypnotics—can cause drowsiness and promote sleep) - even higher doses (anesthetics can cause anesthesia and are used for patient management during surgery)

Naturally occurring depressants

1. Kava Kava plant 2. Datura plant

History

1. bromides were introduced in the 1800s to treat nervousness & anxiety - very popular but toxic 2. replaced by barbiturates in 1900s - initially heralded as safe and effective - apparent problems with tolerance, dependence, and safety 3. in the 1950s the first benzodiazepines were marketed as substitutes for barbiturates. - relatively safe when used for short periods - long-term use can cause dependence and withdrawal problems 4. Benzodiazepines were routinely prescribed for stress, anxiety, or apprehension. - in 1973, 100 million prescriptions were written for benzodiazepines. - twice as many women as men taking them. 5. classified as Schedule V drugs

Datura plant

1. causes hallucinations 2. can cause sedation or induce sleep in small amounts

Other types of CNS depressants

1. drugs with barbiturate-like properties: - chloral hydrate - glutethimide - methyprylon - methaqualone 2. Antihistamines 3. Propofol (abused general anesthetic) 4. GHB (gamma hydroxybutyrate)

Kava Kava plant

1. legally available in health store 2. small amounts = euphoria 3. large amounts = relaxation & sleep

GHB

1. previously sold in health store 2. used by body builders to stimulate release of growth hormones 3. schedule I drug 4. takes effect 10-20 min after ingestion & effects typically last up to 4 hours 5. clear orderless liquid

Patterns of Abuse with CNS Depressants

1. the American Psychiatric Association considers dependence on CNS depressants a psychiatric disorder 2. people most likely to abuse CNS depressants include individuals who: - use drugs to relieve continual stress - paradoxically feel euphoria and stimulation from depressants - use depressants to counteract the unpleasant effects of other drugs of abuse - combine depressants with alcohol and heroin to potentiate the effects 3. Detoxification: The elimination of a toxic substance, such as a drug, and its effects - achieved by substituting a longer-acting barbiturate for the offending CNS depressant and gradually reducing the dose to avoid unpleasant withdrawal effects

Why are CNS depressants problematic?

1. usually prescribed under physician's direction 2. second most frequently abused prescription drug and sometimes contributes to death due to accidental overdoses 3. can cause very alarming and dangerous behavior if not closely monitored 4. seemingly unrelated drug groups can cause CNS depression 5. combination use can cause dangerous drug interactions 6. can cause disruptive personality changes