Adjuvant Pain Medications (Yash's notes)

Corticosteroids

- Dexamethasone

- Methylprednisone [Medrol]]

- Shit ending in 'sone' (I think)

Corticosteroids - Pain use

- Acute/persistent cancer pain, pain secondary to spinal cord or brain compression, neuropathic pain syndromes

Corticosteroids - Action

- Unknown; may involve ability of to decrease inflammation/edema and even shrink tumours

Corticosteroids - Usage

- Avoid high dosage for long term use

Corticosteroids - Side effects

- Hyperglycemia

- Fluid retention

- Dyspepsia, GI bleeding

- Healing impairments

- Muscle wasting, osteoporosis

- Infection susceptibility

TCAs (Tricyclic antidepressants)

- Desipramine

- Nortriptyline

- Imipramine

TCAs - Pain use

- 2nd line drugs for neuropathic pain, continuous/lacinating dysethesias (sharp & shooting), and for pain complicated by depression/insomnia

- May control pain, but not depression

TCAs - Action

- Modulates action of serotonin

- Inhibits ascending pain signals in the dorsal root ganglion or spinal cord itself

TCAs - Side effects

- Somnolence

- Cholinergic effects like constipation, dry mouth, urinary retention, hypotension, cardiotoxicitym confusion

TCAs - Dosage

- Low initial dose (titrate slowly)

- Nortriptyline = 10mg PO bedtime (usual dose up to 50mg max)

- Imipramine = same dose as notriptyline (use instead if sedation effect from other TCAs

Dextromethorphan

- Can help with neuropathic and opioid-resistant pain + cough suppression

Ketamine - Pain use

- Analgesic effects that manage both acute + chronic pain with opioid sparing capabilities

Ketamine - Action

- Inhibits pain signals to brain + produces desired analgesic effects

- Water/lipid soluble (can cross BBB)

- Many different routes of administration

- Preserves respiratory function unlike traditional opioid

Ketamine - Side effects

- Nausea

- Dizziness

- Vomiting

Neuroleptics

- Methrotrimeprazine

- Olazapine

- Risperidone

- Haloperidol

Neuroleptics - Action

- Mechanism unclear; may be involved in dopaminergic pathways and endogenous pain modulation

Neuroleptics - Pain usage

- Acute and chronic pain

- Used when restless, anxious, not sleeping

- Rarely used with TCAs' or anticonvulsants if nerve pain is involved

- Some are good antiemetics (reduce nausea,vomiting, etc.)

Neuroleptics - Side effects

- Sedation

- Orthostatic hypotension

- Anticholinergic effects

- Extra pyramidal symptoms (?)

- Higher fall risk

- Tardive dyskinesia: Repetitive mouth/hand movements; may occur initially or after a period of months in older persons

Neuroleptics - Dosage

- Start low

- Methotrimeprizane: 2.5mg to 5mg PO Q6H-Q8H\

- Haloperidol: Start 0.5mg/day PO, Upper dose 2mg/day

- Riperidones: 0.25mg to 0.5mg BID

Muscle relaxants (Baclofen) - Action

- GABA agonist; works on pain inhibition system

Muscle relaxants - Pain use

- Works on acute, musculoskeletal pain

- Throbbing, aching, and spasm (grabbing type pain)

- Arthritis and MS only if there is muscle spasm

- Stroke related pain

Muscle relaxants - Side effects

- Sedation

- Dizziness

- Ataxia

- Confusion

- Can cause rebound of problem or seizure if stopped suddenly

Muscle relaxants - Dosage

- Begin with initial dose and titrate

- Baclofen: 5mg to 10mg 3-4 times daily

Benzodiazepines

- Lorazepam

- Clonazepam

- Alprazolam

Benzodiazepines - Action/pain

- Acts on pain inhibitory system through NMDA receptors

- Lorazepam: Useful when anxiety/insomnia compound pain/acute muscle spasm

- ClonazepamL Lacinating/paroxysmal neuropathic pain

- GABA agonist

Benzodiazepines - Note

- Can cause dependency with decreasing effectiveness after ~2weeks

- For older persons, only use benzodiazepines with short half-life

- Not recommended for long term use even as hypnotic

- PRN use only due to paradoxical effect/reduced cognition

Benzodiazepines - Side effects

- Sedation/confusion

- Unsteady gait & falls

- May cause sleeplessness or agitation (paradoxical effect)

Benzodiazepines - Dosage

- Start low/drug specific dose

- Lorazepam: 0.25mg to 0.5mg SL bedtime or during day, depending on use

Anticonvulsants

- Gabapentin

- Topiramate

- Pregnabalin

Anticonvulsants - Action

- Acts on pain inhibitory system through NMDA receptors

Anticonvulsants - Pain use

- For neuropathic, lacinating, paroxysmal, or post-stroke pain, headaches, diabetic neuropathy

Anticonvulsants - Side effects

- Gabapentinoids: Dizziness, poor balance, hypotension which increase fall risks + leg edema

- Topiramate: Sedation, unsteady gait, worsened cognition, eye effects, weight loss, contraindicated with those who have history of renal stones

- Pregabilin: Sedation, unsteady gait

- Fewer side effects than TCAs in elders

Anticonvulsants - Dosages

- Gabapentin: Start 100mg daily PO; up to twice daily to up tolerance; max 2400mg

- Topiramate: 25mg to 200mg twice daily PO; gradually titrate to effect/tolerance

- Pregbalin: Start 75mg PO; titrate slowly to 300 mg/day twice daily dosing

Antidepressants

- Bupropion

- Duloxetine

- Amitriptyline [Elavil]

- Neuropathic pain

- Monitor for anticholinergic adverse effects

Topical agents - Pain use

- Local skin analgesic

- Possibly effective for postherapuetic neuralgia

- Must be applied under an occlusive dress or on an anesthetic disc; absorption from genital mucosa and onset is shorter compared to intact skin

Topical agents - Symptoms

- Mild erythema

- Edema

- Skin blanching

Cannabis!!!!!!

- Can help with pain relief (may be placebo; needs more studies)

- Stimulates appetite, helps with nausea

- Spray into whole milk if spray taste isn't liked

- Spray directly into cheek for better buccal absroption