Lec. 2: Sedative-Hypnotic Drugs Flashcards
What are the three main categories of sedative hypnotic drugs?
- Benzodiazepines
- Barbiturates
- Miscellaneous Drugs
What drug further depresses the CNS as dose is increased? (Lethal and therapeutic range are close together)
Barbiturates
What drug has a greater range between therapeutic and lethal doses?
Benzodiazepines
What is a sedative?
A drug that reduces anxiety (anxiolytic) and produces a sense of calm in an individual.
What is a hypnotic?
A drug that induces drowsiness and promotes sleep.
Name five general uses of sedative-hypnotic drugs.
- Anxiolytic (anxiety)
- Anticonvulsant
- Sedative Hynotics
- Central Muscle Relaxant
- Potentiation of CNS Depression
What sedative-hypnotic drug is used to treat anxiety?
Benzodiazepines
What sedative-hynotic drug is used to treat epilepsy?
Barbiturates and Benzodiazepines
What sedative-hypnotic drug is used to treat alcohol detoxification?
Benzodiazepines
What sedative-hypnotic drug is used to treat insomnia?
Benzodiazepines and non-benzodiazepines
What sedative-hypnotic drug is used to treat spasticity (central muscle relaxant)?
Benzodiazepines
What sedative-hypnotic drug is used as an anesthetic (potentiation of CNS depression)?
Barbiturates and benzodiazepines
What determines how onset and duration of action of a drug?
Lipid solubility
Describe the hangover effect of highly lipid soluble drugs.
Drug hangs around in the body and will re-enter the CNS
Name two barbiturates that have a long (8-12 hrs) duration of action.
- Phenobarbital
2. Mephobarbital
Name the barbiturate that has a ultra-short (15-20 min) duration of action.
Thiopental
What is the clinical use of Thiopental?
Anesthesia
What is the clinical use of Phenobarbital?
Hypnotic and Anticonvulsant
What is the clinical use of Mephobarbital?
Anticonvulsant
Name three barbiturates that have an intermediate (2-4 hrs) duration of action.
- Pentobarbital
- Secobarbital
- Amobarbital
Barbiturates bind to ? receptors and increase or decrease the duration of opening of ? ion channels, thus leading to ?-polarization of the neuron.
- GABA
- Increase
- Cl-
- Hyper-polarization
Where are barbiturates metabolized and where are they excreted?
Metabolized in the liver and excreted by the kidneys.
What are the effects of barbiturates on the CNS?
Cause CNS depression from sedation to coma and death.
What are the effects of barbiturates on the respiratory system?
Causes inhibition of ganglionic transmission, decrease in BP, and decreased sympathetic tone
What are the effects of barbiturates on the GI tract?
Decreased tone and contractions of GI and urinary smooth muscle.
***What are the effects of barbiturates on the liver?
Causes induction of cytochrome P-450 enzymes in the liver.
What are six major problems with barbiturates?
- Narrow therapeutic index
- Lethal in overdose
- Rapid development of tolerance that may lead to physical dependence (addiction)
- Cross placental barrier
- Exacerbate Porphyrin synthesis
- Drug interactions result from cytochrome P-450.
Barbiturates cause induction of cytochrome P-450. Why can this be a problem when taking other drugs?
This can lower the therapeutic effectiveness of many drugs.
Name six drug interactions that are created from the induction of cytochrome P-450 enzymes from barbiturates.
- TCA’s
- Anticoagulants
- Quinidine
- Digoxin
- Estrogen
- Antibiotics
Name the three components of the benzodiazepines structure.
- Benzene ring
- Benzene ring
- 7-membered ring (diazepine)