Analgesics 3 Flashcards
Muscle Relaxers
For Spasticity (MS, Cerebral Palsy, etc) and local muscle spasm (epilepsy, hypocalcemia, acute or chronic pain syndromes or m/s injuries)
CNS acting drugs
Diazepam, Baclofen, Tizanidine and one that acts directly on the skeletal muscles; Dantrolene
Centrally acting muscle relaxants
Carisoprodol, Cyclobenzaprine, Diazepam, Metaxalone, Methocarbamol, and Orphenadrine
Baclofen
IND: Spasticity
MOA: Inhibits Tx at the spinal cord level, relief of muscle spasticity
BOX: n/a
CON: Needs renal adjustments
ADR: N/V. CNS effects of somnolence, confusion, dizzy, drowsy
Tizanidine
IND: Spasticity when Baclofen isn’t an option/doesn’t work
MOA: Alpha2 agonist. Increase presynaptic inhibition to reduce facilitation of spinal motor neurons
BOX: n/a
CON: Cirprofloxacin or Fluvoxamine (CYP Inhibitors)
ADR: HYPOtension. Dizzy. CNS effects. Xerostomia. Asthenia.
Dantrolene
IND: Chronic spasticity, malignant hyperthermia, neuroleptic malignant syndrome. 3/4 line option
MOA: Stops SR release of Calcium in skeletal muscle
BOX: Hepatotoxicity, fatal hepatitis
CON: Active hepatic disease
ADR: GI. CNS
Carisoprodol
IND: M/s conditions
MOA: Unknown. Central depressant? anxiolytic? sedative effects?
BOX: Controlled substance; risk of abuse
CON: Hx of acute intermittent porphyria
ADR: CNS EFFECTS (most)
Cyclobenzaprine
IND: Spasm & m/s pain
MOA: Centrally acting muscle relaxant, related to TCAs
BOX: n/a
CON: MAOIs, Hyperthyroidism, Heart failure, arryhthmias, heart blocks, acute recovery of MI
ADR: Xerostomia. CNS
Metaxalone
IND: m/s conditions
MOA: Unknown, a/w depression of nervous system
BOX: n/a
CON: hepatic or renal dysfunction. Anemias
ADR: CNS. GI. Anemias
Methocarbamol
IND: Spasm
MOA: General CNS depression
BOX: n/a
CON: Renal impairment, particularly in injectable version
ADR:CNS. Metallic taste
Orphenadrine
IND: Spasm
MOA: Atropine-like; some euphroic and analgesic effects. Indirect relaxant
BOX: n/a
CON: Glaucoma, GI obstruction, ulcers, prostatic hypertrophy, bladder obstruction, cardiospasm, myasthenia gravis
ADR: Palpitations/tachy. Urine retention. Blurred vision/ increased ocular pressure, mydriasis, nystagmus. constipation
Topical Agents
Advantages: Delivery at site, lower rates of systemic absorption/side effects. Can be used as first line or adjunct.
Topical NSAID: Diclofenac gel; less ADR and now OTC
Topical Lidocaine: Caution in hepatic/renal/cardio dysfunction.
Capsaicin cream: Not super well tolerated. Depletes Substance P
Cannabis
Large systemic review and meta analysis; mixed results for efficacy
Botox
SubQ may reduce opioid requirement in severe post herpetic neuralgia
Ketamine
NMDA antagonist; recent uptick as an IV for complex regional pain syndrome, neuropathic pain, and other intractable pain states
