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
Lidocaine Infusion
Amide local anesthetic. Outpatient settings as an IVPB infusion that can relieve neuropathic pain short term and in some cases sustained analgesia
