Patient OD with TCA and paracetamol. Muscarinic antagonist actions of TCA lead to gastroparesis, keeping the bolus of paracetamol in the gut. Once TCA subside, paracetamol gets churn up, lead to secondary OD, severe liver damage.
Muscarinic antagonist - reduce activity of muscarinic acetylcholine receptors.
Dry mouth, nose
Blurry vision
Gastroparesis, constipation
Urinary retention
Cognitive or memory impairment
Increased body temperature
Tramadol + SSRI = Serotonin syndrome
Tramadol: synthetic analog of codein (opoid) central-acting analgesic, that acts as NMDA-antagonist and SNRI.
Serotonin storm - excess serotonergic activity at CNS and peripheral serotonin receptors. Rapid onset (within minutes).
Cognitive effects: Cognitive impairment, hypomania, hallucination, agitation (hyper-vigilant), headache, coma
Autonomic effects: Shivering (mild), sweating (mild), hyperthermia (mod), hypertension (mod), tachycardia (mild), nausea, diarrhoea (mod), dilated pupils (mild)
Somatic effects: tremor, myoclonus (twitching) (mild), hyper-reflexia (mild)
Pethidin + MAOI/SSRI = Libby Zion
Pethidin: first synthetic opoid (1932). Fast acting opoid analgesic. Mod to severe pain.
Libby Zion (Severe serotonin syndrome) - Tachycardia + hypertension -> shock -> death
Old lady on Lithium 2.0
Lithium is cleared by kidneys. Old ladies with renal impairment, any nephropathy, UTI; Any dehydration or diarrhoeal illness, lead to reduced learance, retain lithium, lithium toxicity.
Lithium toxicity (>2.0 mmol/L)
Rapidly absorbed, renally excreted and toxic to kidne and CNS in high concentrations.Acute toxicity may result in renal failure and death. Prolonged toxic level can cause irreversible brain damage.
Early: worsening tremor, muscular twitches, vomiting. Slurred speech, unsteady gait and impaired consciousness.
Rx: Rehydration and possible dialysis.
Interaction: thiazide dieuretics, antihypertensives (ACEI), or NSAID.
