What do you do if you overdose on TCA?
Administration of intravenous sodium bicarbonate as an antidote has been shown to be an effective treatment for resolving the metabolic acidosis and cardiovascular complications of TCA poisoning.
How does sodium bicarbonate work in TCA overdose?
The benefit of sodium bicarbonate in the setting of TCA overdose is probably due to both an increase in serum pH and the increase in extracellular sodium.
Why are tricyclic antidepressants so toxic in overdose?
TCAs are rapidly absorbed in the gastrointestinal tract. However, following an overdose, owing to the inherent anticholinergic effects, TCAs may decrease the gastrointestinal motility and cause delayed absorption and toxicity. Coingestion of other anticholinergic medications may cause more erratic absorption.
When do you administer sodium bicarbonate in TCA overdose?
Consider gastric lavage only if within one hour of a potentially fatal overdose. Give 50 grams of charcoal if within one hour of ingestion. Give sodium bicarbonate (50 ml of 8.4%) if: pH <7.1.
How is morphine overdose treated?
Morphine overdose often requires special treatment. If you have access to the opioid-antagonist drug called naloxone, do not hesitate to administer to counter the overdose. The compound suppresses an overdose by binding to the same receptors as morphine in the central nervous system.
How does TCA overdose cause seizures?
Furthermore, they block neurotransmitter reuptake (norepinephrine, serotonin) at central presynaptic terminals, and this may be the mechanism by which seizures are induced by TCA overdose. Probably their most important pharmacologic effect in terms of mortality is myocardial sodium channel blockade.
How do you use sodium bicarbonate injection?
For mild acidosis, the usual dosage is 1 to 2 mEq per kg of body weight, administered slowly. For more severe acidosis, 2 to 5 mEq per kg of body weight may be administered over a 4 to 8 hour period. Subsequent therapy is dependent on the clinical response of the patient.
What is the pH of sodium bicarbonate?
8.5
Sodium bicarbonate is a white powder with molecular formula NaHCO3, and pH of 8.5 (1% aqueous solution, 25°C). Among sodium compounds, it is one of the substances with the lowest alkalinity.
Are tricyclic antidepressants lethal in overdose?
Tricyclic antidepressants (TCA) are one of the common causes of a fatal drug overdose. They have a narrow therapeutic window so can be fatal at relatively lower doses and single tablet fatalities have been reported. Its most serious effects are cardiovascular and CNS instability.
How does TCA cause hypotension?
They also block alpha receptors peripherally and thus can cause hypotension. Furthermore, they block neurotransmitter reuptake (norepinephrine, serotonin) at central presynaptic terminals, and this may be the mechanism by which seizures are induced by TCA overdose.
Can you overdose on sodium bicarbonate?
Overdose of sodium bicarbonate (sodium bicarbonate 5% injection) may result in a severe degree of alkalosis which may be accompanied by hyperirritability or tetany. Should alkalosis result, the bicarbonate should be stopped and the patient managed according to the degree of alkalosis present.
How do tricyclic antidepressants cause hypotension?
Is there a link between SSRIs and hyponatremia?
Current evidence suggests a relatively higher risk of hyponatremia with SSRIs and venlafaxine, especially when combined with patient risk factors, warranting clinicians to be aware of this complication.
Which is more common, SSRI or TCA overdose?
According to the database, TCA overdose accounted for 1.12 exposures per 10,000 population in 1992. Recently, the trend for antidepressant overdose has shifted more towards SSRIs. However, the rate of hospitalization is higher in cases of TCA overdose compared to SSRI, because of the narrower therapeutic index with TCAs.
How is tricyclic antidepressant toxicity treated in the hospital?
Tricyclic Antidepressant Toxicity Treatment & Management 1 Prehospital Care. Endotracheal intubation is necessary in a patient who is obtunded and unable to protect the airway… 2 Emergency Department Care. The greatest risk of seizures and arrhythmias occurs within the first 6-8 hours of cyclic antidepressant (CA) ingestion. 3 Consultations.
What are the risk factors for hyponatremia?
Patient risk factors included older age (odds ratios = 6.3) and concomitant use of (thiazide) diuretics (odds ratios = 11.2-13.5). Conclusion: Hyponatremia is a potentially dangerous side effect of antidepressants and is not exclusive to SSRIs.