ANXIOLYTICS
GAD (Generalised Anxiety Disorder)
The noradrenaline pathways in generalised anxiety disorder
In GAD there is increased noradrenaline transmission from the subcortex (amygdala, locus coeruleus, the caudal raphe nuclei). This is associated with anxiety, and may mediate the autonomic symptoms associated with stress such as increased heart rate, dilated pupils, tremor and sweating.
Theory: Anxiety & panic may result from poor brain inhibition.
Benzos may reset the (overactive) amygdala.
Anxiolytics: Benzodiazepines
The first benzodiazepine, chlordiazepoxide (Librium®) was discovered serendipitously in 1954 by the Austrian scientist Dr Leo Sternbach (1908-2005), working for the pharmaceutical company Hoffmann-La Roche. Initially, he discontinued his work on the compound Ro-5-0690, but he "rediscovered" it in 1957 when an assistant was cleaning up the laboratory.
In 1963 approval for use was given to diazepam (Valium) - a simplified version of Librium - primarily to counteract anxiety symptoms.
Anxiolytics: Benzodiazepines
Intro. 1960s - quickly became the most widely used class of drugs.
Produce dependency.
Agonists: facilitates the binding of GABA at the post-synaptic neuron -- depressing its excitability.
Psych. effects from action in the limbic system; side effects (sedation, increased seizure threshold, amnesia, muscle relaxation) from action in the cerebral cortex & brain stem.
Anxiolytics: Benzodiazepines
Pharmacokinetics
Well absorbed orally.
Peak plasma levels in about one hour.
Elderly metabolize slower, and are at risk for cognitve side (toxic) effects.
Anxiolytics: Benzodiazepines
Pharmacological Effects of “complete agonists” -- actions similiar to Valium (diazepam)/
alleviate: anxiety, agitation, fear.
anti-epileptic
side (toxic) effects of: confusion, amnesia, muscle relaxation.
Anxiolytics: Benzodiazepines
Uses
Tx. of Anxiety & Panic
Insomnia
ETOH withdrawal
Adjunct to epilepsy tx.
Anxiolytics: Benzodiazepines
Side Effects (Toxicity)
Dose related extensions of the intended actions.
Sedation, drowsiness, ataxia, lethargy, confusion, motor impairment, cognitive impairment, disorientation, slurred speech, amnesia.
Anxiolytics: Benzodiazepines
Tolerance, Dependence, Dangers.
A pattern of dependence can develop even following a therapeutic dose
Potentiates with CNS depressants.
Withdrawal can include increased anxiety, insomnia, agitation; and, rarely, hallucinations and seizures.
Freely cross the placenta, so fetus will be subject of effects of the drug. Can cause birth defects during the 1st trimester. Benzos in plasma are also available in milk of mother.
BuSpar (buspirone)
Unique anxiolytic.
No significant sedation, minimal cognitive effects. Low potential for addiction.
Does not potentiate with CNS depressants.
Antidepressant effect too.
Gradual onset.
May reduce irritability and aggression.
3 comments:
the book said that the date rape drug was a benzo
where did you read that? I did not get that anywhere. However, it would make sense that the date rape drug would be a benzo since many people that report being drugged with the date rape drug have no memory from the incident and also reported a rapid onset of the drug. It would be interesting to read more about date rape drug stats.
None of the "date rape" drugs discussed in the article, presented in class, are benzos.
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