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Biologist, M.D.;  Future M.D., FPCP, FPCC, Funny and Awesome guy.

Wednesday, July 24, 2013

Barbiturate Overdose/Barbiturate Poisoning due to use of Barbiturates as Treatment for Seizures/Epilepsy

[Med Stuff Time!]

Seizures/Epilepsies can occur to everyone when the right moment is triggered. Triggering factors may include head injury, trauma, febrile (fever)/illness, CNS damage, Family history, Genetic predisposition or it may even be Idiopathic.

Children (0-12 years) and the elderly (above 50) are the population most at risk for seizures. For the elderly, the usual underlying cause of seizures are Cerebrovascular diseases.

Seizures occur when the predisposing factors cause a possible decrease in inhibitory flags in the brain, leading to activation of Calcium channels, influx of Sodium into the cell and therefore causing a lot of action potentials. When these action potentials trigger other neurons (normally this won't happen but in patients with triggering factors, neurons CAN and WILL FIRE synchronously) and they all fire synchronously, a seizure wave begins and the patient then exhibits the signs and symptoms of a seizure. 

Barbiturates are used to treat seizures. One example is Phenobarbital, which is a known anti-seizure drug. Barbiturates bind to the GABA receptors in order to  increase the GABA mediated inhibitory factors so as to prevent abnormal excitation of many neurons.

Barbiturates, in a normal dosage, can be cleared via hepatic metabolism and renal excretion. However, in overdose, barbiturates can in fact cause further CNS depression because of the longer time it would take to clear the drug from the body (also, consider the large amount of it in a patient overdosed with this!). 

CNS depression symptoms include hypotonia, hypoventilation, hypotension, drowsiness, occasional apnea and many others. 

Treatment should be done quickly in order to prevent worsening of symptoms that may lead to brain death, cardiac arrest and of course, whole body death. Treatment schemes include supportive (giving of Oxygen, Activated charcoal) and hemodialysis (in order to increase rate of clearance.

Here is a sample conceptual map made by yours truly:

Concept map done by yours truly, JV Aclan :)
Alternative treatment/drugs for seizures are benzodiazephenes, diazepam, among others.

Harrison's Principles of Internal Medicine 18th Ed
Katzung Basic and Clinical Pharmacology 11th Ed
Lots of journals from NEJM, PubMed, Science Direct

Just my 2 cents!

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