Unit 5: Pain Management and Seizure Medications

Morphine: Use (Opioid prototype)

Used for relief of moderate and severe pain

Decreases the sensation AND emotional reaction to pain

Morphine MOA

Binds to both Mu and Kappa receptors to produce profound analgesia

Morphine adverse effects

- Constipation

- Respiratory depression

- Urinary retention

- N&V

- Cough suppression

- Vasodilation (hypotension and flushing)

Why is Fentanyl dangerous?

- It is very potent

- It is 20 to 40 times more potent than heroin and 100 times more potent than morphine

- Overdose risk is very high

A synthetically manufactured opioid

What is OxyContin? Therapeutic use?

Extended release Oxycodone

- A semi-synthetic opioid used medically for treatment of moderate to severe pain

- Highly addictive and commonly abused drug

Hydromorphone (Dilaudid) Therapeutic use

- Moderate-to-severe pain (alone and in combination with nonopioid analgesics)

- Extended-release product for opioid-tolerant patients requiring around-the-clock management of persistent pain.

- Antitussive (lower doses)

Hydromorphone MOA

- Binds to opiate receptors in the CNS

- Alters the perception of and response to painful stimuli while producing generalized CNS depression

- Suppresses the cough reflex via a direct central action

Hydromorphone adverse effects

- Confusion

- Sedation

- Respiratory depression

- Hypotension

- Constipation

- N&V

- Flushing

Toradol (kertolac) Use and common side effects

- Very strong NSAID for only short term (< 5 days)

- Acute and moderately severe pain that occurs following surgery

Can cause GI side effects and can increase bleeding

Tramadol

Opioid analgesic

- For moderate general and nerve related pain

- Also lowers seizure threshold

What is Tramadol prescribed for?

Back Pain

Anxiety

Depression

Fibromyalgia

Obsessive Compulsive Disorder

Restless Legs Syndrome

Chronic Pain

Tramadol side effects

Nausea and sedation

What is Methadone?

- Long acting synthetic opioid used to reduce withdrawal symptoms in people addicted to Heroin or other narcotic drugs without causing a "high"

- Also used for severe pain when other no other options have worked

- Highly regulated

Gabapentin Use

- Treats neuropathic pain

- Increases seizure threshold to decrease seizures

Gabapentin MOA

Inhibits Ca channels to decrease neuronal activity

Gabapentin side effects

- CNS depression

- Dizziness

- Sleepiness

- Decreased alertness

- Dry mouth

Don't use in pts with kidney disease

Key principles of Opioid administration

- Start low, go slow

- Start with short acting to titrate effective dose

- Once pain control achieved, switch to long acting meds

- Provide breakthrough/loading dose

What is Naloxone (Narcan)

- An opioid antagonist that temporarily reverses the effects of opioid overdoses

- Restores breathing within 2 to 5 minutes

- Only in body for 20-90 minutes -> may need to be used multiple times until overdose passes

What are the three classes of NSAIDs

- Salicylates (ie ASA)

- Ibuprofen and ibuprofen-like drugs

- COX-2 antagonists (ie celecoxib)

NSAID indications

- Analgesic

- Anti-inflammatory

- Antipyretic

- Anticoagulant (salicylates)

NSAID MOA

Salicylates and Ibuprofen:

- Inhibit prostaglandin synthesis of COX1 and COX2

COX2 antagonists ex. Celecoxib

- Inhibits prostaglandin synthesis of COX2

NSAID adverse effects

- GI bleeding

- Acute renal failure

- Increased risk of MI and stroke

- Hepatotoxicity

Therapeutic use of Acetaminophen

- Mild to moderate pain

- Osteoarthritis of the hip or knee

- Dysmenorrhea

- Dental procedures

- Headache and myalgia

- Fever

MOA of Acetaminophen

Inhibits COX activity in CNS but not in rest of body

Adverse effects of Acetaminophen

- Hepatotoxicity

- Renal failure

- Pancytopenia

What is Aspirin

- Aspirin unlike other NSAIDS has a potent antiplatelet effect so the potential for bleeding must be carefully monitored

High doses may cause salycylism which includes symptoms of

- Tinnitus

- Dizziness

- Headache

- Sweating

What are immunosuppressants

- Inhibits pts immune system

- Used for auto immune disease, transplant pts

- They are toxic to bone marrow

—> Decreased WBC, RBC, and platelets

—> At risk for infection, decrease O2, and bleeding

Ex. Methotrexate, corticosteroids

What are Barbiturates?

Indicated primarily for tonic-clonic seizures, but also used as sedative, hypnotic and general anaesthetic purposes

Ex. Pentobarb, Phenobarb

What are Benzodiazepines

Indicated primarily for absence and myoclonic seizures but also used as anxiolytic and sedative

- Ex. Diazepam, Lorazepam

Phenobarbital use

- Indicated for most seizure types except absence seizure

- Anxiolytic, sedative, hypnotic

Phenobarbital MOA

- Increases activity of GABAa receptor, reducing excitability of post-synaptic neurons

- Increases seizure threshold

Phenobarbital adverse effects

-Drowsiness, sedation, excitation (children), difficulty focusing, confusion, depression, headache

- N&V

- Loss of appetite

- Vitamin deficiencies (D, B12, folate)

- Anemia (impairs bioactivation of vitamins in the liver)

- Overdose - CNS depression, respiratory depression, coma, death

Diazepam (Valium) Use

• Status epilepticus

• Prevention of seizures

• Anti-anxiety, sedative, hypnotic; often used prior to procedure

• General anaesthetic

Diazepam MOA

• Stimulates GABA receptors in brain, reducing neuronal discharges

Diazepam adverse effects

- Drowsiness, fatigue, dizziness

- Vertigo

- Ataxia

- Laryngeal spasms

- Urinary retention

- Menstrual irregularities

- IV delivery - risk of muscle weakness, hypotension, respiratory depression

Lorazepam (Ativan) Use

- Status epilepticus

- Anxiety

- Decreases seizures

MOA of Lorazepam

Stimulates GABA receptors in brain, reducing neuronal discharges

Lorazepam adverse effects

- drowsiness, dizziness, unsteadiness

- respiratory depression

- N&V

- hypotension

Rapid IV use:

- Apnea

- Cardiac arrest

Phenytoin (Dilantin) Use

• Prophylactic therapy of all seizures except absence

Phenytoin MOA

• Delays influx of sodium ions in neurons

• Slows propagation and spread of abnormal discharges

• Phenytoin has many interactions!

Phenytoin adverse effects

- Lethargy, drowsiness, dizziness

- Headache

- Bradycardia, hypotension

- Agranulocytosis, leukopenia, thrombocytopenia

- Gingival hyperplasia

- Rashes

- Weight loss

- Hepatotoxicty

- Can cause toxicity

Signs of Phenytoin toxicity

Coma

Slow or slurred speech

Confusion

Staggering gait or walk

Fever

Swollen gums

Tremor

Involuntary, jerky, repeated movement of the eyeballs (nystagmus)

Unsteadiness

Lethargy

Low blood pressure

Uncoordinated movements

N&V

Sleepiness

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