Actions of Barbiturates (3)
- GABAA Agonists (Open Cl- Channels)
- Decrease Activation of AMPA
- Decrease Activity of Voltage Dep Na+ Channels (Inhib High Freq Firing)
What Are Barbiturates used for (4)?
- Dec Intracranial and Cerebral Edema
Affects of Barbiturates with increasing dosages (5):
What have barbiturates been replaced with?
Which drugs are the proptype for sedative hypnotics?
Which Barbiturates are used for Induction (2)?
Which Barbiturates are used for short term anesthesia maint (2)?
Which Barbiturate is used to treat insomnia?
Which Barbiturates are used to Tx seizures?
Which is a more potent AMPA atagonist, Pentobarb or Phenobarb?
Which is more likely to induce profound CNS depression, Pentobarb or Phenobarb?
Which Barbiturates are used for preoperative sedation?
Phenobarb's acts on which receptors?
Activity of Phenobarb on it's receptors:
- GABA: Increases the activity of GABA by opening the Cl- channels
- Glutamate: Non-Comp agonist of AMPA
____ has a high affinity & selectivity
Why have benzodiazapams replaced barbiturates?
- Less profound effects on induction
Barbiturate's primarily differ in what property?
Bezodiazapam lipid solubility =>
- Enter brain rapidly
- Short Duration of action
How do Benzodiazapines act as antiepileptics?
Inhibit AMPA receptor mediated exitatory transmission
How do benzodiazapines protect the brainfrom ischemic damage?
- Neuronal activity suppression
- Barbituate coma
- Reduced O2 consumption & perfusion
Clinial uses of benzodiazapines:
- Muscle Relaxant
At high dosages, benzodiazapines => (2)
Acute Barbituate intoxication =>
Serous deficits on Cardiovascular and Peripheral functions
The affects of what drugs are dependent on dosage, route, and the species treated?
Side Fx of Barbiturates (7):
- Depression of Medullary Center
- Respiratory Depression-Arrest
- GI Tract
- Reduced O2 consumption of all tissues
- Decreased basal metaboic rate
- Reduced response to ACh
Which organs are most affected by barbiturates?
- Liver (hepatic microsomal enzymes)
- Kidney (D/T hypotension)
What factors affect the distribution of barbiturates?
- Lipid Solubility
- Plasma Protein Binding
- Emotional & Physiological State
Which barbiturates are highly lipid Soluble (enters brain and tissues rapidly)?
When administered PO or IV, how are barbiturates metabolised?
First Pass Metab >> Liver
Which Barbiturate is metabolized (? absorbed) transmucosally?
Barbiturates induce liver microsomal enzymes, which leads to:
increased rate of metabolism of many drugs
Barbiturates enhance the metabolism of (8): *
- Other sedatives/hyonotics
- Steroid Hormones
- Bile Salts
- Vit A & K
It is important to check liver function before admin of _____
What drugs should be used with caution in cats? Why?
Barbiturates -> Respiratory Depression
Which drugs have a low therpeutic index?