Psychopharmacology – Other Psychoactive Drugs Flashcards
Benzodiazepines:
Benzodiazepines include diazepam (Valium), alprazolam (Xanax), and lorazepam (Ativan).
Benzodiazepines are effective for short-term management of anxiety, insomnia, and seizures, but their long-term use should be avoided due to the risk of dependence and other adverse effects. They should be used cautiously, particularly in older adults, and never in combination with alcohol due to the risk of serious complications.
Benzodiazepines: Uses
Anxiety disorders.
Insomnia.
Seizures.
Alcohol withdrawal.
Benzodiazepines: Mechanism
Increase the activity of gamma-aminobutyric acid (GABA), a neurotransmitter that inhibits the activity of neurons, leading to calming effects.
Benzodiazepines: Side Effects
Drowsiness and sedation (common).
Weakness and unsteadiness.
Impaired memory and concentration.
Anticholinergic effects.
Sexual dysfunction.
Paradoxical effects (e.g., excitability, anxiety).
Tolerance, dependence, and withdrawal symptoms with chronic use.
Rebound anxiety and depression, anorexia, delirium, seizures with withdrawal.
Lethal synergistic depressant effect when combined with alcohol.
Benzodiazepines: Precautions
Use with caution in older adults due to the risk of disorientation and confusion.
Avoid long-term use due to the risk of tolerance, dependence, and withdrawal symptoms.
Gradually taper off benzodiazepines to avoid withdrawal symptoms.
Barbiturates - Definition
Central nervous system depressants, including thiopental, amobarbital, and secobarbital.
Barbiturates: Uses
Anesthesia induction, anxiety, insomnia, and certain types of seizures.
Barbiturates: Mechanism of Action
Enhances GABA activity, leading to neuronal hyperpolarization and reduced excitability.
Barbiturates: Side Effects
Drowsiness, dizziness, confusion, ataxia, paradoxical excitement, respiratory depression, dependence, withdrawal.
Barbiturates: Precautions
Short-term use, cautious tapering, avoidance of alcohol and other depressants.
Barbiturates: Considerations
Limited use due to high risk of dependence, tolerance, and withdrawal. Prefer safer alternatives for anxiety and insomnia.
Azapirones
Definition: Anxiolytic drugs, including buspirone (BuSpar).
Uses: Generalized anxiety disorder and other anxiety disorders.
Mechanism of Action: Partial agonist at serotonin receptors, particularly 5-HT1A receptors.
Side Effects: Dizziness, dry mouth, sweating, nausea, headache.
Advantages: Non-sedating, lacks dependence and tolerance development.
Precautions: Slow onset of action, may not be effective for severe anxiety.
Considerations: Suitable for long-term use, especially in patients prone to substance abuse or dependence.
Narcotic-Analgesics (Opioids)
Drugs mimicking effects of endorphins/enkephalins.
Narcotic-Analgesics (Opioids)
Types
Natural opioids (opium, morphine, heroin, codeine), synthetic opioids (methadone, oxycodone, hydrocodone, fentanyl).
Narcotic-Analgesics (Opioids)
Uses
Pre-surgery anesthesia, pain management, heroin detox (methadone).
Narcotic-Analgesics (Opioids)
Mechanism
Bind to opioid receptors, inhibit pain signals.
Narcotic-Analgesics (Opioids)
Side Effects
Dry mouth, nausea, pupil constriction, drowsiness, constipation, respiratory depression.
Overdose Effects: Convulsions, coma, death.
Narcotic-Analgesics (Opioids)
Chronic Use Risks
Dependence, tolerance, withdrawal (flu-like symptoms, insomnia, cramps).
Narcotic-Analgesics (Opioids)
Public Health Concerns
Leading cause of accidental deaths in the US (opioids).
Narcotic-Analgesics (Opioids)
Treatment
Medication-assisted therapy, rehabilitation programs, naloxone for overdose.
Beta-Blockers
Function: Inhibit sympathetic nervous system activity.
Uses: Hypertension, cardiac arrhythmias, migraine, essential tremor.
Example: Propranolol (Inderal).
Additional Use: Anxiety treatment, especially for somatic symptoms.
Side Effects: Hypotension, decreased libido, insomnia, nausea, dry eyes, dizziness, depression.
Discontinuation: Abrupt withdrawal contraindicated (rebound hypertension, tremors, headaches).
Mood Stabilizers
The mood stabilizers are used to treat bipolar disorder and include lithium and anticonvulsant medications.
Lithium
Function: First-line drug for acute mania and classic bipolar disorder.
Brand Names: Eskalith, Lithobid.
Common Side Effects: Nausea, vomiting, diarrhea, metallic taste, increased thirst, weight gain, hand tremor, fatigue, impaired memory, and concentration.
Monitoring: Regular lithium levels check to avoid toxicity.
Toxicity Symptoms: Seizures, coma, death.
Anticonvulsant Drugs
Uses: Treat acute mania and bipolar disorder with mixed episodes.
Examples: Carbamazepine (Tegretol), valproic acid (Depakene).
Side Effects: Nausea, dizziness, sleepiness, lethargy, ataxia, tremor, visual disturbances, impaired concentration.
Monitoring: Blood levels to avoid liver failure (valproic acid, carbamazepine), agranulocytosis, aplastic anemia (carbamazepine).
Drugs for Treating Alzheimer’s Disease
Cholinesterase Inhibitors: Delay breakdown of acetylcholine.
Examples: Tacrine (Cognex), donepezil (Aricept), rivastigmine (Exelon), galantamine (Razadyne).
Approved for mild, moderate, and severe Alzheimer’s disease (except tacrine).
Side Effects: Vary but can include gastrointestinal issues, dizziness, and insomnia.
NMDA Receptor Antagonist: Regulates glutamate activity.
Example: Memantine (Namenda).
Approved for moderate to severe Alzheimer’s disease.
Side Effects: May include dizziness, headache, and confusion.
Psychostimulants for ADHD
Types: Methylphenidate (Ritalin, Concerta), pemoline (Cylert), amphetamine-dextroamphetamine (Adderall).
Purpose: First-line treatment for ADHD.
Effects: Increase attention, concentration; reduce hyperactivity, impulsivity.
Mechanism: Increase dopamine, norepinephrine activity in prefrontal cortex.
Side Effects: Insomnia, nervousness, decreased appetite, weight loss, abdominal pain.
Concerns: Growth suppression in children (reversible with “drug holidays”).
College Use: Some use by students, but evidence suggests limited cognitive enhancement.
Atomoxetine (Strattera)
Other Drugs for ADHD
Purpose: Non-stimulant medication for ADHD.
Mechanism: Selective norepinephrine reuptake inhibitor.
Effects: Improves attention, reduces impulsivity and hyperactivity.
Side Effects: Nausea, decreased appetite, insomnia, fatigue.
Guanfacine (Intuniv)
Other Drugs for ADHD
Purpose: Alpha-2 adrenergic agonist used for ADHD.
Mechanism: Stimulates alpha-2 receptors, reducing sympathetic outflow.
Effects: Improves attention, reduces impulsivity.
Side Effects: Sedation, fatigue, dizziness, hypotension.
Disulfiram (Antabuse)
Drugs for Alcohol Use Disorder
Purpose: Causes unpleasant symptoms when alcohol is consumed.
Effects: Nausea, vomiting, shortness of breath, headache.
Mechanism: Inhibits alcohol metabolism, leading to acetaldehyde buildup.
Naltrexone (ReVia)
Drugs for Alcohol Use Disorder
Purpose: Reduces cravings and pleasurable effects of alcohol.
Effects: Decreased alcohol cravings.
Mechanism: Opioid antagonist, blocks alcohol-induced euphoria.
Acamprosate (Campral)
Drugs for Alcohol Use Disorder
Purpose: Reduces alcohol cravings.
Effects: Decreased desire to drink alcohol.
Mechanism: Modulates neurotransmitter systems involved in alcohol dependence.
Tetrahydrocannabinol (THC)
Description: Main active ingredient in cannabis.
Effects: Psychoactive; stimulates dopamine release in ventral striatum.
Function: Acts on mesolimbic dopaminergic reward pathway.
Medication: Dronabinol oral solution (Syndros).
Approved Uses:
Treatment of anorexia and weight loss in AIDS patients.
Management of chemotherapy-induced nausea and vomiting in cancer patients unresponsive to other antiemetics.
Drug Half-Life
Definition: Time needed for blood level of drug to decrease to 50% of peak level.
Use: Determines time interval between doses.
Short Half-Life: Shorter interval between doses.
Long Half-Life: Longer interval between doses.
Age-related Changes: Older adults may have longer half-life due to metabolism changes.
Prescribing Rule: “Start low and go slow” for older adults due to increased sensitivity and longer half-life.
Example: Benzodiazepines have longer half-life in older adults, requiring longer elimination time.
Drug Tolerance and Cross-Tolerance
Tolerance Definition: Gradual reduction in drug effects with repeated use.
Effect: Higher doses needed for same effect.
Cross-Tolerance: Tolerance to one drug extends to others in same class.
Example: Tolerance to alcohol leads to tolerance to benzodiazepines and barbiturates.
Mechanism: Shared pharmacological actions among drugs in same class.
Clinical Implications: Increased risk of overdose, dependence, and withdrawal.
Therapeutic Index (TI)
Definition: Measures a drug’s safety.
Therapeutic Index (TI)
Calculation
Animal Studies: LD50/ED50
Human Studies: TD50/ED50
Therapeutic Index (TI)
LD50 (Lethal Dose 50)
Minimum dose lethal to 50% of test sample.
Therapeutic Index (TI)
ED50 (Effective Dose 50)
Minimum dose producing desired effect in 50% of sample.
Therapeutic Index (TI)
TD50 (Toxic Dose 50):
Minimum dose causing toxicity in 50% of sample.
Therapeutic Index (TI)
TI Value
TI ≤ 1.0: Narrow therapeutic window, higher risk.
TI > 1.0: Wide therapeutic window, lower risk.
Therapeutic Index (TI)
Clinical Implications
Narrow TI requires close monitoring.
Wide TI indicates safer drug.
