Week 8: Substance Use

Substance Use Disorders: Definition

• chronic, relapsing medical conditions

• involves dysregulation of brain reward, motivation, memory, and inhibitory control

• key features: impaired control, craving, risky use, social impairment, physio;ogic dependence

Dopamine Reward Pathway Overstimualtion

• reinforces the compulsion to seek the drug above all else

• intense stimuli cause massive dopamine surges, overriding natural rewards

Glutamate Dysregulation

• impaired learning and memory around cues and triggers

• causes the brain to form powerful, long-lasting associations between environmental cues (triggers) and the substance

Reduced Prefrontal Cortex Activity

• poor impulse control and decision-making

• chronic use of substances physically weakens the area of the brain responsible for executive function

Dependence

• physiological state where the body has adapted to the presence of a drug and requires it to function "normally" on a cellular level

Addiction

• a behavioral and psychological condition characterized by a loss of control and compulsive use despite significant negative life consequences.

Withdrawal

• physiologic response when substance is absent

• the body struggles to recalibrate its baseline

• CNS hyperactivity

Tolerance

• the brain becomes less sensitive to a drug

• requiring higher doses to achieve the original effect

Intoxication

• acte effects of substances on CNS

• often euphoric, sedated, impulsive, or altered sensorium

Opioid: Intoxication Patho

• opioids target mu receptors

• initially suppressing pain and triggering a surge of dopamine that reinforces the "high” (CNS depression)

Opioid : Intoxication Signs

• ↓ LOC

• pinpoint pupils

• slow GI mobility → constipation

• HoTN, bradycardia

Opioid: Withdrawal Patho

• occurs when opioids removed after chronic use

• ↑ norepinephrine release

• not usually fatal, but extremely uncomfortable

Opioid: Withdrawal Signs

• rhinorrhea (runny nose)

• sweating

• goosebumps

• tachycardia

• yawning

• bone pain

• diarrhea

• irritability

Harmful Reduction

• approach that acknowledges that people may continue to use substances

• goal: reduce negative health outcomes, not require abstinence

• supports autonomy, dignity, and safety

Harmful Reduction: Core Principles

1. meet people where they are

2. focus on safety

3. prioritize engagement and trust

4. respect patient goals

5. promote, non-punitive, trauma-informed care

6. recognize substance use as a health issue, not a moral failure

Opioid Use: Harm Reduction in Practice

• offer naloxone + education

• encourage never using alone

• discuss safe injection practices

• encourage medication treatment

Chemsex

• consuming drugs to enhance sexual activity

• may lead to risky behaviors:

  • transmitting HIV, Hepatitis C, and other STIs

Opioid Agonist-Antagonist

• buprenorphine (sublingual)

• MOA: depress CNA and alter pain perception

• Use: opioid dependence, opioid use disorder

Opioid Agonist-Antagonist (Buprenorphine) Considerations

• decreases potential for abuse

• safe during labor

• possible liver or renal failure

• dental problems

Buprenorphine: Nursing Priority

• ensure the patient is in active, moderate withdrawal before first dose

  • COWS score

• giving it too early while other opioids are still active will cause "precipitated withdrawal”

Long-Acting Opioid Agonist Use

• methadone

• synthetic

• Use: chronic pain management, treatment of opioid use disorder

• prevents withdrawal, reduces cravings

Methadone: Safety

• long half-life

• risk of respiratory depression

• risk of QT prolongation

• monitor EKG in cardiac patients

• high overdose risk if combined with benzodiazepines

• no “ceiling effect”

Ceiling Effect

• drug effects plateau at a maximum level

Opiod Antagonist

• naloxone

• MOA: attaches to the same receptors as opioids

• Uses: opioid overdose, reversal of respiratory depression

• Reactions: severe agitation/ delirium/ HTN

Naloxone: Warnings

• drug works within 2 to 5 minutes

• naloxone wears off quickly

  • monitor the patient closely for "re-narcotization”

  • the patient may stop breathing again once the naloxone levels drop

• will cause immediate, intense withdrawal symptoms for opioid dependent patients

  • agitation, vomiting, ↑ HR, HTN

Alcohol Intoxication

• CNS depression, slowed cognition, ataxia, impaired judgment

• High levels → respiratory depression, hypoglycemia, coma

Alcohol Withdrawal

• 6-48 hours since last drink

• CNS becomes hyperexcitable

  • GI distress

  • "the shakes" (fine tremors)

  • anxiety/ palpitations

  • insomnia

Alcohol Withdrawal: Severe Stage

• 48-96 hours since last drink

• delirium tremens

  • life-threatening instability

  • profound disorientation

  • visual or tactile hallucinations

  • hypertension

  • hyperthermia

  • tonic-clonic seizures

Chronic Alcohol Use: Hepatic Effects

• steatosis → hepatitis → cirrhosis

• (fatty liver disease) → (inflammation of liver) → (liver scarring)

Chronic Alcohol Use: Cardiovascular Effects

• cardiomyopathy (weakened heart muscle)

• arrhythmias

• increased risk of stroke

Chronic Alcohol Use: Neurological Effects

• peripheral neuropathy

  • damage to the peripheral nerves (causes pain, weakness, tingling

• Wenicke-Korsakoff syndrome - severe thiamine (vitamin B) deficiency

  • acute confusion (Wernicke’s encephalopathy)

  • permanent memory loss with confabulation (Korsakoff’s psychosis)

Chronic Alcohol Use: Hematologic Effects

• folate deficiency

• anemia

• bone marrow suppression

Clinical Institute Withdrawal Assessment for Alcohol

• CIWA-Ar

• diagnostic scale used by nurses to objectively monitor the severity of alcohol withdrawal and guide medication dosing

Benzodiazepine

• Uses:

  • first-line treatment for acute alcohol withdrawal

  • prevents seizures and delirium tremens

• monitor for oversedation, respiratory depression, and ataxia (unsteadiness)

• dosage based on the patient's CIWA-Ar score

Opioid Antagonist

• naltrexone

• MOA: blocks the mu-opioid receptors involved in the reward and pleasure circuits of the brain

• Use: treats alcohol and opioid use disorders

Naltrexone: Nursing Priority

• the patient needs been opioid-free for 7 to 10 days before starting naltrexone

• opioid antagonist

  • will trigger immediate, severe withdrawal if opioid are still in their system

• poor medication adherence = a long-acting IM injection (Vivitrol) can be given once every 4 weeks to provide steady coverage

Glutamate Modulator: Acamprosate

• MOA: modulating the glutamate system and potentially the GABA system

• Use: helping to "rebalance" brain chemistry that has been chronically disrupted by long-term alcohol use

• reduce the "negative" symptoms of abstinence

  • insomnia, anxiety, and restlessness, which often lead patients to relapse

Aldehyde Dehydrogenase Inhibitor: Disulfiram

• MOA: inhibiting the enzyme acetaldehyde dehydrogenase

• Use: treats chronic alcoholism by creating an unpleasant sensitivity to alcohol

• CAUTION: CANNOT have any alcohol with it

Disulfiram: Cautions

• consuming even small amounts of alcohol will trigger a violent physical reaction

• causes a toxic buildup of acetaldehyde in the blood

  • flushing, throbbing headache, nausea, vomiting, chest pain, palpitations, and dyspnea

• avoid "hidden" alcohol sources

  • mouthwash, cough syrups, vanilla extract, aftershave

• contraindicated in patients with severe cardiovascular disease, psychosis, or significant liver impairment

Nicotine Effect on the Brain

• nicotine stimulates nicotinic acetylcholine receptors

• massive dopamine release in reward pathway

• nicotine also stimulates the adrenal glands

  • release epinephrine (adrenaline)

  • acutely ↑ HR, BP, and blood glucose levels

Nicotine: Chronic Use

• Up-Regulation: the brain compensates for the constant stimulation by increasing the number of receptors

• creates tolerance

  • meaning the user needs more nicotine to achieve the same effect

Nicotine Withdrawal

• leads to irritability, anxiety, restlessness, insomnia, difficulty concentrating, increases appetite

• peaks 24-72 hours, lasts weeks

Nicotine Replacement Therapy

• Uses: smoking cessation support, reduces withdrawal and cravings

• provides a controlled, lower dose of nicotine without the harmful toxins and carcinogens found in tobacco smoke

The Transdermal Patch (Long-Acting)

• provides a steady, continuous level of nicotine over 16 to 24 hours to prevent the "trough" that triggers morning cravings

• instruct patients to rotate sites daily on a clean, hairless area above the waist

Nicotine Patch: Safety

• if the patient experiences vivid dreams or insomnia, they should remove the patch at bedtime

• the patch must be removed before an MRI to prevent skin burns from the metallic backing

Nicotine Gum

• short-acting

• Use: for breakthrough cravings

• patients must use the "chew and park" method

• chewing until a peppery taste or tingling occurs

• then "parking" it between the cheek and gum to allow for mucosal absorption

Nicotine Gum: Patient Education

• instruct patients not to drink acidic beverages (coffee, juice, soda) for 15 minutes before or during use

• acidity prevents nicotine absorption in the mouth

Nicotine Lozenge

• short-acting

• lozenge is a transmucosal delivery system that should be allowed to dissolve slowly in the mouth

• not to be chewed or swallowed

  • which would cause GI upset and poor absorption.

Partial Nicotinic Receptor Agonist

• varencline

• Use: most effective single agent for smoking cessation

• Patho: reduces cravings + withdrawals

  • prevents the "reward" if a patient smokes

Varencline: Nursing Priority

• monitoring for changes in behavior, hostility, agitation, depressed mood, or suicidal ideation

• black box warning was removed

• typically started one week before the patient’s actual quit date to allow the medication to reach steady-state levels in the brain

• assess for new or worsening symptoms of cardiovascular disease

  • (like chest pain or SOB)