OTC Drug Toxicity: Caffeine, Theophylline, and Antihistamine

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Questions and Answers

What is the approximate acute toxic dose of caffeine?

  • 5-10 g (correct)
  • Over 50 g
  • 1 g
  • 20-30 g

Which cardiovascular effect may be observed in caffeine toxicity?

  • Bradycardia
  • Hypotension
  • Hypertension
  • Ventricular fibrillation (correct)

What is the treatment for supraventricular tachycardia in caffeine toxicity?

  • Lignocaine
  • Beta-adrenergic antagonists (correct)
  • Cardioversion
  • Calcium channel blockers

What is a common symptom of theophylline toxicity related to oral tablets?

<p>Nausea (C)</p> Signup and view all the answers

What is an uncommon symptom of theophylline toxicity?

<p>Coma (C)</p> Signup and view all the answers

Which symptom is NOT associated with theophylline toxicity?

<p>Bradycardia (A)</p> Signup and view all the answers

What is the first step in the treatment of theophylline toxicity?

<p>Gastric lavage (D)</p> Signup and view all the answers

Which mechanism is proposed for the toxicity of methylxanthines?

<p>Increased calcium release from intracellular sites (C)</p> Signup and view all the answers

Which of the following is true about the distribution of caffeine and theophylline in tea leaves?

<p>Both are equally distributed in tea leaves (C)</p> Signup and view all the answers

How are xanthine derivatives eliminated from the body?

<p>Through the liver metabolism (B)</p> Signup and view all the answers

What is the half-life of xanthine derivatives in nonsmokers?

<p>3 to 15 hours (B)</p> Signup and view all the answers

Where is caffeine commonly found?

<p>Coffee, tea, chocolate, and cola beverages (C)</p> Signup and view all the answers

Which source contains the highest amount of caffeine?

<p>Brewed coffee (C)</p> Signup and view all the answers

Which compound is metabolized by the liver to methylxanthine and methyluric acid derivatives?

<p>Theophylline (C)</p> Signup and view all the answers

What is the main mechanism that appears to cause nausea and vomiting due to methylxanthine toxicity?

<p>Stimulation of chemoreceptor trigger zone (C)</p> Signup and view all the answers

What is the common half-life of xanthine derivatives in adult smokers?

<p>4 to 5 hours (D)</p> Signup and view all the answers

What is the chemical class of caffeine, theophylline, and theobromine?

<p>Alkaloids (A)</p> Signup and view all the answers

What are the main compounds found in tea leaves?

<p>Caffeine, theophylline, and theobromine (C)</p> Signup and view all the answers

What is the proposed mechanism for methylxanthines toxicity?

<p>Inhibition of cyclic nucleotide accumulation (D)</p> Signup and view all the answers

What is the main mechanism of toxicity of methylxanthines?

<p>Increased calcium release from intracellular sites, Accumulation of cyclic nucleotides (especially cAMP), Adenosine receptor blockade</p> Signup and view all the answers

What is the approximate half-life of xanthine derivatives in nonsmokers?

<p>3 to 15 hours</p> Signup and view all the answers

Which compounds are naturally occurring xanthine derivatives?

<p>Caffeine, Theophylline, Theobromine</p> Signup and view all the answers

Where is caffeine ubiquitously distributed?

<p>Coffee, Tea, Chocolate, Cola beverages</p> Signup and view all the answers

What is the distribution time for xanthine derivatives after oral absorption?

<p>Within two hours</p> Signup and view all the answers

Which organ metabolizes the compounds to methylxanthine and methyluric acid derivatives?

<p>Liver</p> Signup and view all the answers

What is the source containing the highest amount of caffeine?

<p>Brewed coffee</p> Signup and view all the answers

What is the main cause of nausea and vomiting in methylxanthine toxicity?

<p>Direct stimulation of the chemoreceptor trigger zone</p> Signup and view all the answers

What is the approximate acute toxic dose of caffeine?

<p>200-400 mg</p> Signup and view all the answers

What is the treatment for supraventricular tachycardia in caffeine toxicity?

<p>Adenosine</p> Signup and view all the answers

What is the main route of elimination for xanthine derivatives from the body?

<p>Kidney</p> Signup and view all the answers

What are the xanthine derivatives metabolized into by the liver?

<p>Methylxanthine and methyluric acid derivatives</p> Signup and view all the answers

What are the potential cardiovascular effects of caffeine toxicity?

<p>Tachycardia, ventricular fibrillation, and cardiopulmonary arrest</p> Signup and view all the answers

How can potentially lethal ingestions with life-threatening complications be managed in caffeine toxicity?

<p>Charcoal haemoperfusion</p> Signup and view all the answers

What are the common symptoms of theophylline toxicity related to controlled-release dosage forms?

<p>Convulsions, hypothermia, ataxia, visual hallucinations</p> Signup and view all the answers

What are the metabolic disturbances associated with theophylline toxicity?

<p>Hypokalaemia, hyperglycaemia, hypercalcaemia, and metabolic acidosis</p> Signup and view all the answers

What are the treatment options for hypotension refractory to fluids and vasopressors in theophylline toxicity?

<p>Alpha-adrenergic drugs such as levarterenol</p> Signup and view all the answers

What are the common initial symptoms associated with caffeine withdrawal?

<p>Headache, anxiety, fatigue, and craving behavior</p> Signup and view all the answers

What are the signs of antihistamine toxicity?

<p>Tremors, excitable auditory and visual hallucinations, dry mouth, dry, hot skin, heart palpitations</p> Signup and view all the answers

What is the proposed mechanism for caffeine withdrawal?

<p>Demonstrated abruptly within 12 to 24 h after the last dose, initial symptoms last for about one week</p> Signup and view all the answers

What is the proposed mechanism for tolerance to theophylline?

<p>Tolerance to the diuretic action and the insomnia, but no tolerance develops to the CNS stimulation or bronchodilation</p> Signup and view all the answers

What are the potential treatment options for hyperthermia and rhabdomyolysis in theophylline toxicity?

<p>Dantrolene, hydration, and maintenance of high urine output</p> Signup and view all the answers

What are the indications for haemoperfusion in theophylline overdose?

<p>Intractable convulsions, persistent hypotension, uncontrollable arrhythmias, and serum theophylline levels greater than 60 to 80 mcg/ml</p> Signup and view all the answers

What are the symptoms of caffeine toxicity related to theophylline?

<p>Nausea, cardiac arrhythmias</p> Signup and view all the answers

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