depressants

Question 1

Benzodiazepines

Answer 1

Decrease the anxiety, fear, and apprehension
Increase the pain threshold
Decrease the salivary flow and the vomiting reflex
Allow the use of a lower dose of local anesthetics
Muscle relaxant and anticonvulsant
Decrease BP
Decrease in respiratory rate

Question 2

Benzodiazepines

Answer 2

Rapid absorption - Oral
Peak in blood - 1 to 4 hours
Eliminated in feces and urine
not recommended for geriatrics because of cumulative toxicity
Lack of support for triazolam in pediatric dentistry
Large therapeutic window – relatively safe when used alone
Reversal agent: Flumazenil – GABA receptor antagonist

Side effects:Blurred vision, headache, confusion
Generally an extension of their therapeutic effect

Question 3

Flumazenil

Answer 3

Brand name is Romazicon
Used for
Benzodiazepine overdose
Excessive sedation reversal
High dose BZD dependency
A continuous “trigger” audit highly recommended for dental practice
Available as 0.1mg/ml
Onset of action is rapid (1-2 minutes)
Recommended dose for adults is 200 μg every 1–2 minutes until the effect is seen, to a maximum of 3mg per hour
Possible side effects: tachycardia, seizure

Question 4

Propofol (Diprivan)

Answer 4

Induction agent for general anesthesia
Positive modulation of GABA
Rapid onset of action (~ 2 minutes)
Very narrow therapeutic index requires close patient monitoring (Importance of dosing)
Has no analgesic properties
Cardiac side effects (cardiac arrhythmia and hypotension)
Addictive agent with potential for abuse but NOT classified as a Controlled Substance by the DEA

Question 5

Ketamine

Answer 5

NMDA receptor antagonist (inhibits N-Methyl-D-aspartate receptor)
Very short-acting CNS Depressant
Hallucinogeniceffects from IV administration is about 1 Hr.
Anesthetic and analgesic
Causes Dissociative Anesthesia (distorted perceptions of sight and sound and feelings of detachment)
Illicitly used as a hallucinogen – (Special K, Date-rape drug)
Does not provide anxiolysis observed in benzodiazepines
Dose: 1 to 2 mg/kg IV
Not recommended for pediatric use

Question 6

Ketamine – Common Adverse Effects

Answer 6

Psychological reactions (agitation, confusion, psychosis) as it wears off
Increase in blood pressure
Muscle tremors
Does not have an antidote
Overdose requires symptomatic & supportive care
Do not use or use with caution in:
Patients less than 18 years of age
Hypersensitivity to ketamine
Pregnancy or breastfeeding
History of seizures
Unstable cardiac dysrhythmia
Ischemic heart disease
Uncontrolled hypertension
Severe hepatic dysfunction
History of psychosis
Hydrocephalus

Question 7

Barbiturates

Answer 7

Short-acting barbiturates such as pentobarbital and secobarbital are the preferred drugs of abuse.
Barbiturates are dangerous drugs, with a narrow therapeutic index between the dose required for sedation and the dose that will cause coma and death.
Physiologically addicting if taken in high doses over 1 month or more.
Pregnant women who take barbiturates during the third trimester can give birth to addicted infants who undergo an extended withdrawal syndrome

Question 8

barbiturates

Answer 8

Thiopental induces anesthesia in 30 seconds. Used in combination with a muscle relaxant
Anticonvulsant
Pain and anxiety – now replaced with safer and more effective agents
High doses are used for assisted suicide or euthanasia
Amobarbital slow IV injection is used as “truth serum”