Pharmacology Quiz on Colchicine and Glycosides

Medicinal Seeds

• Psyllium:

  • Derived from Plantago psyllium, Plantaginaceae family
  • Psyllium husk is a concentrated source of dietary fiber, containing arabinoxylan
  • Arabinoxylan is a viscous, water-soluble fiber that attracts and binds with water, forming mucilage
  • Used as a bulk-forming laxative for constipation treatment and stool softener for hemorrhoids
  • Psyllium generally produces a bowel movement within 12 to 72 hours.
  • Caution: Take with sufficient liquid and at least half an hour after other medications to prevent delayed medication absorption.
  • Potential side effects: gas, bloating, abdominal cramps, dehydration, diarrhea, bloating, abdominal cramps, vomiting, nausea, rectal irritation, lazy bowel, constipation (if taken long-term)
  • Improper use, especially with low fluid intake can lead to esophageal or intestinal obstruction.

• Nutmeg:

  • Derived from Myristica fragrans, Myristicaceae family, dried ripe seeds deprived of aril and seed coat
  • Chemical constituents: volatile oil (myristicin [2-5%], elemicin [1-2.5%]), fixed oil (30-40% [palmitic, stearic, oleic acid]), triterpene saponins, sterols
  • External uses: rheumatism, neuralgia, upper respiratory tract disorders (oil)
  • Popular spice, safe in small amounts (2 tsp or 5g)
  • Toxicity (large amounts): hallucinations, adverse symptoms, serious complications, or even death
  • Overdose toxicity: Myristicin is active at 5-HT (serotonin) receptors in the brain, leading to hypotension, sedative, and hallucinogenic properties; and large doses cause severe hyperexcitability followed by CNS depression
  • Bioconversion of myristicin in doses of 1 to 3 nuts can generate amphetamine derivatives
  • Treatment for toxicity: gastrointestinal emptying (inducing vomiting, gastric lavage), and activated charcoal administration

• Colchicum seed:

  • Derived from Colchicum autumnale, Liliaceae family
  • Contains at least 0.5% colchicine as a trupolone alkaloid.
  • Uses: Gout treatment
    • Uric acid dissolves in blood, passes through kidneys into urine
    • Uric acid buildup forms sharp needle-like urate crystals in joints or around tissues, causing pain, inflammation, and swelling.
    • Colchicine reduces the body's response to uric acid crystals
    • Colchicine reduces the number of white blood cells that travel to inflamed areas.
    • Colchicine helps break the inflammation and pain cycle of a gout attack.
  • Other uses: Familial Mediterranean fever (FMF) treatment (reduces attack frequency, improves quality of life)
  • Severity of poison: extremely poisonous, symptoms such as stomachaches, diarrhea, nausea, vomiting, and intestinal hemorrhages

• Nux vomica seed (poison nut):

  • Derived from Strychnos nux vomica, Loganiceae family, dried ripe seeds
  • Chemical constituents: Indole alkaloids (strychnine and brucine) [2.0% to 5.0%]
  • Severe toxicity due to strychnine
  • No recommended use
  • Strychnine poisoning symptoms (after ingestion of one bean): initial restlessness, equilibrium disorders, stiff neck and back muscles; later, painful muscle spasms, followed by convulsions of the entire body
  • Lethal dosage for adults: 50 mg strychnine
  • Treatment: activated charcoal, anticonvulsants, and muscle relaxants, possibly respiratory ventilation

• Strophanthus seed (arrow poison):

  • Derived from Strophanthus kombe, S. gratus, Apocynaceae family, dried ripe seeds deprived of awns.
  • Chemical constituents: Cardioactive glycosides, including 4-8% ouabain (G-strophanthin), rhamnoside glycoside more stable than other cardiac glycosides found elsewhere
  • Uses: cardiac insufficiency, hypotension
  • Ouabain: A cardial glycoside similar to digoxin, inhibits Na+/K+ ATPase pump, increasing intracellular calcium and improving cardiac cell contractility used to treat congestive heart failure, hypotension, and arrhythmias
  • Ouabain is not currently approved for use in the USA.
  • Ouabain is highly toxic (LD50 5mg/kg)
  • Ouabain overdose symptoms: rapid twitching of the neck, respiratory distress, rapid/irregular heartbeat, increased blood pressure, convulsions, and cardiac arrest
  • Drug interactions:quinidine, calcium salts, laxatives, and glucocorticoids enhance both effects and side effects