1) What effect does increasing the lipid solubility of barbiturates have on the duration of action?
- Decreases duration of action
2) What are the mechanism(s) of action of barbiturates?
- Gaba receptor agonists which enhance inhibitory neurotransmission
- Block glutamate binding at AMPA receptors
- Depress the reticular activating system
3) What are the clinical uses of barbiturates?
- Anticonvulsants
- Euthanasia agents
- General anesthetics
4) Where are barbiturates metabolizedand by which enzymes?
- Liver
5) Where are barbiturates excreted?
- Kidneys
6) What are the expected CNS effects associated with administration of barbiturates?
- Decrease cerebral blood flow
- Decrease cerebral oxygen consumption
- Decreased intracranial pressure
- Decreased intraocular pressure
7) What are the expected cardiovascular effects associated with administration of barbiturates?
- Decreased stroke volume
- Minimal change in cardiac output
8) Under what conditions should barbiturates be used cautiously?
9) Which barbiturate may precipitate ventricular arrhythmias?
10) Why should barbiturates be avoided in patients undergoing splenectomy?
11) Define euthanasia.
- Ending the life of an individual animal in a way that minimizes or eliminates pain and distress
12) In the US, which barbiturates are approved for euthanasia of dogs?
- Pentobarbital-phenytoin products
13) What happens to a patient following IV injection of pentobarbital + phenytoin sodium administered for the purpose of euthanasia?
- Rapid unconsciousness and simultaneous collapse with rapid progression to deep anesthesia and hypotension
- Depression of medullary respiratory center results
14) Is pentobarbital allowed for use in food animals?
- NO in food animals
15) How would accidental exposure of a patient to pentobarbital be treated?
16) Which patient are considered at-risk patients for barbiturate use?
- Poor liver function
- Little body fat
- Preexisting illnesses that cause acidosis
17) Why is it essential that ultra-short acting barbiturates be injected IV?
- Can cause tissue necrosis if given outside of the vein
18) What are the 3 classifications of barbiturates based on duration of action?
- Long-acting, short acting, and ultrashort-acting
19) What are the 2 classifications of barbiturates based on the chemical side chain of the barbituric acid molecule?
- Oxybarbiturates
- Thiobarbiturates
20) Describe the solubility of thiobarbiturates.
- Highly soluble in fat
21) Where do thiobarbiturates redistribute after leaving the CNS?
- Goes to the fat stores of the body
22) Give an example of a long-acting oxybarbiturate.
- Oxybarbiturates
23) Give an example of short-acting oxybarbiturate.
- Pentobarbital
24) Give an example of an ultrashort-acting thiobarbiturate.
- Thiobarbiturates
25) What is the primary indication for phenobarbital use?
- Anticonvulsant to prevent epileptic seizures
26) What DEA schedule is phenobarbital?
- IV
27) How is phenobarbital administered?
- Oral route
28) What is the primary indication for pentobarbital use?
- Euthanasia agent
29) What DEA schedule is pentobarbital?
- II
30) How is pentobarbital administered?
- IV or IP
31) Why must thiobarbiturates be administered IV?
- To avoid necrosis and tissue sloughing
32) Why should thiobarbiturates be used cautiously in thin animals?
- Redistributes to fat stores in body
33) What may happen if a thiobarbiturate is administered too rapidly through the IV route?
- Apnea
34) What may happen if a thiobarbiturate is administered too slowly through the IV route?
- CNS excitement
35) What adverse side effects may occur with the use of barbiturates?
- Excessive CNS depression
- Paradoxical CNS excitement
- Severe respiratory depression
- Cardiovascular depression
- Tissue perfusion
36) What is the main component of most euthanasia agents?
- Pentobarbital
37) What DEA schedule is pentobarbital alone?
- Class II
38) What DEA schedule is pentobarbital sodium?
- Class III
39) What are potential adverse side effects of euthanasia agents?
- Muscle twitching
- Death may be delayed
- Perivascular irritation
40) What type of barbiturate is methohexital sodium?
- Ultrashort-acting oxybarbiturate
41) How does the potency of methohexital compare to thiopental?
- Twice as potent
42) What DEA schedule is methohexital?
- IV
Barbiturates
1) What effect does increasing the lipid solubility of barbiturates have on the duration of action?
- Decreases duration of action
2) What are the mechanism(s) of action of barbiturates?
- Gaba receptor agonists which enhance inhibitory neurotransmission
- Block glutamate binding at AMPA receptors
- Depress the reticular activating system
3) What are the clinical uses of barbiturates?
- Anticonvulsants
- Euthanasia agents
- General anesthetics
4) Where are barbiturates metabolizedand by which enzymes?
- Liver
5) Where are barbiturates excreted?
- Kidneys
6) What are the expected CNS effects associated with administration of barbiturates?
- Decrease cerebral blood flow
- Decrease cerebral oxygen consumption
- Decreased intracranial pressure
- Decreased intraocular pressure
7) What are the expected cardiovascular effects associated with administration of barbiturates?
- Decreased stroke volume
- Minimal change in cardiac output
8) Under what conditions should barbiturates be used cautiously?
9) Which barbiturate may precipitate ventricular arrhythmias?
10) Why should barbiturates be avoided in patients undergoing splenectomy?
11) Define euthanasia.
- Ending the life of an individual animal in a way that minimizes or eliminates pain and distress
12) In the US, which barbiturates are approved for euthanasia of dogs?
- Pentobarbital-phenytoin products
13) What happens to a patient following IV injection of pentobarbital + phenytoin sodium administered for the purpose of euthanasia?
- Rapid unconsciousness and simultaneous collapse with rapid progression to deep anesthesia and hypotension
- Depression of medullary respiratory center results
14) Is pentobarbital allowed for use in food animals?
- NO in food animals
15) How would accidental exposure of a patient to pentobarbital be treated?
16) Which patient are considered at-risk patients for barbiturate use?
- Poor liver function
- Little body fat
- Preexisting illnesses that cause acidosis
17) Why is it essential that ultra-short acting barbiturates be injected IV?
- Can cause tissue necrosis if given outside of the vein
18) What are the 3 classifications of barbiturates based on duration of action?
- Long-acting, short acting, and ultrashort-acting
19) What are the 2 classifications of barbiturates based on the chemical side chain of the barbituric acid molecule?
- Oxybarbiturates
- Thiobarbiturates
20) Describe the solubility of thiobarbiturates.
- Highly soluble in fat
21) Where do thiobarbiturates redistribute after leaving the CNS?
- Goes to the fat stores of the body
22) Give an example of a long-acting oxybarbiturate.
- Oxybarbiturates
23) Give an example of short-acting oxybarbiturate.
- Pentobarbital
24) Give an example of an ultrashort-acting thiobarbiturate.
- Thiobarbiturates
25) What is the primary indication for phenobarbital use?
- Anticonvulsant to prevent epileptic seizures
26) What DEA schedule is phenobarbital?
- IV
27) How is phenobarbital administered?
- Oral route
28) What is the primary indication for pentobarbital use?
- Euthanasia agent
29) What DEA schedule is pentobarbital?
- II
30) How is pentobarbital administered?
- IV or IP
31) Why must thiobarbiturates be administered IV?
- To avoid necrosis and tissue sloughing
32) Why should thiobarbiturates be used cautiously in thin animals?
- Redistributes to fat stores in body
33) What may happen if a thiobarbiturate is administered too rapidly through the IV route?
- Apnea
34) What may happen if a thiobarbiturate is administered too slowly through the IV route?
- CNS excitement
35) What adverse side effects may occur with the use of barbiturates?
- Excessive CNS depression
- Paradoxical CNS excitement
- Severe respiratory depression
- Cardiovascular depression
- Tissue perfusion
36) What is the main component of most euthanasia agents?
- Pentobarbital
37) What DEA schedule is pentobarbital alone?
- Class II
38) What DEA schedule is pentobarbital sodium?
- Class III
39) What are potential adverse side effects of euthanasia agents?
- Muscle twitching
- Death may be delayed
- Perivascular irritation
40) What type of barbiturate is methohexital sodium?
- Ultrashort-acting oxybarbiturate
41) How does the potency of methohexital compare to thiopental?
- Twice as potent
42) What DEA schedule is methohexital?
- IV