Anxiolytic + Sedative Drugs

Question 0

Thiopental (Pentothal)

Answer 0

Ultra-short acting barbiturate. Acts within 1 minute from IV administration

Question 1

Receptor site for both barbiturates and benzodiaepines

Answer 1

While not the actual GABA receptor, these drugs bind an adjacent receptor which will change the conformation of the nearby GABA receptor, increasing it’s affinity for GABA. This causes more frequent and prolonged opening of the chloride channel(s) of the neuron, decreasing nerve transmission.

Question 2

Pentobarbitol / Nembutal

Answer 2

Short acting barbiturate. Active 15-30’ after PO adminstration, duration 6-8h.

Question 3

Butalbital (Fiorinal)

Answer 3

Intermediate acting barbiturate. Onset 20-40’ after PO adminstration, duration up to 6h.

Question 4

Phenobarbital (Luminal)

Answer 4

Long-acting barbiturate. Onset 1h after PO adminstration, duration ~12h. Primarily used to tx seizure disorders.

Question 5

Barbiturate SFx?

Answer 5

Drug tolerance, dependence, severe (potentially fatal) withdrawal sxs, potential for respiratory depression and coma if EtOH is consumed with drug.

Question 6

Midalozam (Versed)

Answer 6

Benzodiazepine. Potent sedative, hypnotic, anxiolytic, muscle relaxant and anticonvulsant. Used often to manage aggressive, violent and/or delirious pts.

Question 7

Diazepam (Valium)

Answer 7

Benzodiazepine. Used as anxiolytic, sedative, muscle relaxant and anti-convulsive.
MAO - Binds to benzo R in CNS to enhance GABA activity. PO, IV. Rapid oral absoption. Metabolized to active constituents in liver, prolonging drug action.
SFx: Drowsiness, impaired mentation, tolerance, addiction. Rebound insomnia may occur with abrupt discontinuation.

Question 8

Zolpidem (Ambien)

Answer 8

Short-acting non-benzo hypnotic. Used to induce sleep.
MOA - binds GABAa receptors (same location as benzos). PO. Onset ~15’, half life 2-3h. Effective for inducing sleep but not maintaining sleep.

Question 9

Eszopiclone (Lunesta)

Answer 9

Benzodiazepine-like hypnotic. Used for insomnia.
MOA - Potentiates GABA by binding specific R site, unrelated to benzos. PO. Rapid onset.
SFx: Impaired mentation

Question 10

Ramelteon (Rozerem)

Answer 10

Melatonin R agonist.

MOA - Binds melatonin R MT1 and MT2, enhancing action of endogenous melatonin.

Question 11

Benzodiazepine Withdrawal

Answer 11

Pt who have been on benzos for a long time and/or at a high dose are susceptible to potentially severe withdrawal symptoms, which may include seizure and death. Pts must taper down their medicine rather than abruptly discontinuing.

Question 12

Flumazenil / Romazicon

Answer 12

Benzodiazepine receptor antagonist that can rapidly reverse the effects of benzodiazepines.
IV. Rapid onset of action (1 to 2 minutes) but a half-life of only approximately one hour. Multiple doses must be given to maintain reversal of the benzodiazepine particularly with patients who have over- dosed on longer acting benzodiazepines.
Flumazenil is less effective at reversing respiratory depression than CNS depression in benzo OD.