Barking Up the Wrong Tree (Cinohonism, Quinine & Quinidine)

In this episode Ryan and Toxo discuss some potential toxic spices and break down the toxicity and treatment of a once well known medicine Cinchona Bark, Quinine, and Associated ToxicitiesHistorical PerspectiveUse of Cinchona Bark Powder for Malaria:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4973170/Evolutionary Pressure of Malaria on Sickle Cell Traits:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3499995/CinchonismDefinition: Classic toxicities caused by ingestion of quinoline derivatives from cinchona bark.Brief Review:https://pubmed.ncbi.nlm.nih.gov/32644745/EtiologySources:Powdered cinchona bark: Used in tonic water, to treat restless legs, or as a remedy for certain viruses.Prescription quinoline derivatives:QuinineQuinidineHydroxychloroquineChloroquineClinical EffectsSymptoms:Dizziness, flushing, headache, tinnitus.Potential for vision loss.Laboratory Abnormalities:Hypoglycemia, hypokalemia, long QRS.TreatmentSupportive Care:Manage airway, breathing, and circulation (ABCs).Early use of epinephrine as a preferred pressor based on animal and chloroquine data.Correct Endocrine/Metabolic Abnormalities:Hypertonic Sodium: For wide QRS (use cautiously to avoid worsening hypokalemia).Decontamination:Consider multi-dose activated charcoal for significant ingestions.Ocular ToxicityKey Findings:Ocular toxicity is often delayed but can become permanent.Quinine levels >15 are associated with increased ocular toxicity.Quinine-induced blindness: https://pubmed.ncbi.nlm.nih.gov/3983356/Hall AP, et al. Quinine-induced blindness. Br J Ophthalmol. 1997. doi:10.1136/bjo.81.12.1029Recovery:Vision may recover centrally first, then peripherally.Hyperbaric oxygen therapy (HBO) is often used but remains debated.OtotoxicityMechanism:Tinnitus caused by microstructural changes in the outer hair cells of the cochlea and organ of Corti.Vasoconstriction and prostaglandin inhibition contribute to decreased hearing.Studies:Jastreboff PJ, et al. Quinine-induced tinnitus in rats. Arch Otolaryngol Head Neck Surg. 1991. doi:10.1001/archotol.1991.01870220110020Roche RJ, et al. Quinine induces reversible high-tone hearing loss. Br J Clin Pharmacol. 1990. doi:10.1111/j.1365-2125.1990.tb03704.xMore on Toxicity from StudiesCardiac Arrhythmias in Patients Taking Quinine Alone:Padmaja UK, Adhikari P, Periera P. Experience with quinine in falciparum malaria. Indian J Med Sci. 1999. PMID: 10695226.Negative Inotropic Effects of Quinidine:Hoffmeister HM, et al. Negative inotropic effect of class-I antiarrhythmic drugs. Eur Heart J. 1987. doi:10.1093/oxfordjournals.eurheartj.a062178.Tinnitus and Hearing Effects: Jarboe JK, Hallworth R. The effect of quinine on outer hair cell shape, compliance and force. Hear Res. 1999. doi:10.1016/s0378-5955(99)00031-3.A Morel DilemmaSupport the showReview the show where ever your listeningGet Messages from Toxo (Join the Newsletter!)Join as a supporting memberAd free episodesBonus content and early accessDiscounts and give aways on GOTA PICCEM Mushroom card gameThe GOTTA PICCEM Poisonous Mushroom Game!The Poisonus Fungus Amongus Children's Book!Full book reading (6 minutes!)Tox trinkets (Rep the show at home!)Reach the showEmail: [email protected] Show ResourcesRyan's Medical Games and ResourcesShow Website