Anticonvulsants & Antidepessants

ANTICONVULSANTS


Pharmacologic Properties of Anticonvulsants

General Properties

  • Anticonvulants are a diverse group of pharmaceuticals used in the treatment of epileptic seizures. Thus, they are also referred to as Antiepileptics.
  • They primarily alter the transmission of nerve impulses to prevent epileptic seizures.
epileptic seizure
Generic Names
  1. Carbamazepine
  2. Ethosuximide
  3. Phenobarbital
  4. Phenytoin (dilantin-brand)
  5. Primidone (metabolite phenobarb)
  6. Valproic Acid

Analysis of Anticonvulsants
  • Immunoassay technique- It is the method of choice.
    • it only takes a few minutes
    • the test is fairly simple
    • centrifugal analyzers allows batch processing of large numbers of samples
  • Gas Chromatography or HPLC
    • requests for multiple drug assays
    • study of drug metabolites might be of value
This video shows us how Phenytoin (anticonvulsant) works. 



ANTIDEPRESSANTS
Antidepressants


General Properties

     2 Major classes
  • Tricyclic antidepressants
    • act by blocking the uptake of norepinephrine and serotonin by the presynaptic nerve endings. This blockage prolongs the time of transmission of the nerve impulse.
    • They are used slowly and cautiously
    • Frequently ineffective in the relief of depression
    • Administered orally
  • Monoamine oxidase inhibitors (MAOIs)
    • Effective in treating atypical depression
    • They are not widely used because of their effect on blood pressure

Assay Techniques 
  • Gas Chromatography
    • most effective means of therapeutic drug monitoring for Tricyclics
    • It is preferred because multiple drugs may be given and active metabolites are often present
    • The specific compounds can be separated and quantitated, and the total amount of active drugs can be reported.
    • It also permits identification of specific antidepressants.

Side Effects and Toxic Signs

Overdosage

  • Overdose of Tricyclics
    • ingestion of more than the therapeutic dose 
    • Attempted suicide with tricyclics
  • Effects of overdosage on the cardiovascular system
    • Impairment of cardiac function
  • Elevated amount produces respiratory depression and seizures.