Chapter 11
Antianxiety Agents
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Antianxiety Agents
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An individual’s response to dental treatment can range
from total relaxation to severe apprehension.
Each dental patient should be assessed at each
appointment for his or her stress level.
Each patient should then be provided with the least
stressful environment as possible while receiving
dental treatment.
Stress or anxiety due to dental treatment can be
treated with both pharmacologic and
nonpharmacologic methods.
The treatment of choice is often dependent upon the
patient and his or her stress level.
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Antianxiety Agents
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Benzodiazepines
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The benzodiazepines are the most commonly
used drugs to treat anxiety.
 These drugs are well absorbed after oral
administration.
 Benzodiazepines are highly lipid-soluble and
have a quick onset of action.
 They easily cross the blood-brain barrier.
 They are metabolized in the liver and excreted
in the kidneys.
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Antianxiety Agents
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Benzodiazepines
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Mechanism of Action
• Benzodiazepines bind to benzodiazepine receptors
in the CNS and act as agonists.
• They enhance the action of the inhibitory
neurotransmitter γ-aminobutyric acid (GABA).
• This decreases excitation in the limbic system.
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Antianxiety Agents
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Benzodiazepines
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Pharmacologic Effects
• Behavioral Effects
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Reduce anxiety and panic.
Cause sedation.
• Anticonvulsant Effects
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Prevent the spread of seizures in tissues surrounding
the anatomic seizure focus.
• Muscle Relaxation

Skeletal muscle relaxation
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Antianxiety Agents
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Benzodiazepines
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Adverse Reactions
• Adverse effects are simply an extension of the drugs’
pharmacologic effects.
• Central Nervous System
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They are many and include: fatigue, drowsiness,
muscle weakness, ataxia.
• Anterograde Amnesia
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This effect when the drug is taken and can last up to
several hours after.
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Antianxiety Agents
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Benzodiazepines
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Adverse Reactions
• Respiratory Effects
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Can produce respiratory depression
• Cardiovascular Effects
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Therapeutic doses have no effect on circulation.
• Visual Effects
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Can produce diplopia, nystagmus, blurred vision
• Dental Effects
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Xerostomia, increased salivation, swollen tongue,
bitter or metallic taste
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Antianxiety Agents
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Benzodiazepines
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Abuse, Tolerance, and Overdose
• Abuse, and physical dependence and tolerance have been
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reported with benzodiazepine use.
Psychological dependence can occur with large doses
over an extended period of time.
Benzodiazepines have a very wide therapeutic index.
Excessively large doses must be used to achieve overdose
because of their therapeutic index.
Overdose is treated with supportive measures.
In some instances, the benzodiazepine antagonist
flumazenil is used to treat overdose.
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Antianxiety Agents
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Benzodiazepines
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Uses
• The short-term treatment of anxiety, panic attacks,
insomnia, and alcohol withdrawal.
• Some benzodiazepines are used to treat seizure
disorders.
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Antianxiety Agents
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Antianxiety Agents
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Barbiturates
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These drugs are the original sedative-hypnotics.
 They have a very narrow therapeutic index.
 They have been associated with a high rate of
abuse and complete respiratory and cardiovascular
depression.
 They are lethal in an overdose.
 Benzodiazepines have pretty much replaced
barbiturates in treating anxiety, insomnia and panic
because of their more acceptable safety profile.
 Barbiturates are used to treat seizure disorders
and to induce general anesthesia.
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Antianxiety Agents
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Barbiturates
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These drugs are well-absorbed both orally and
rectally.
 They are metabolized by the liver and excreted
by the kidneys.
 They produce their pharmacologic effect by
enhancing GABA receptor binding.
 Pharmacologic effects include central nervous
system depression, analgesia, and
anticonvulsant effects.
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Antianxiety Agents
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Barbiturates
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These drugs are relatively safe at usual
therapeutic doses. CNS depression can be
exaggerated in elderly patients and in those with
liver or renal failure.
Higher doses can be lethal.
Chronic long-term use can lead to physical and
psychologic dependence.
Barbiturates are contraindicated in persons with
intermittent porphyria.
Barbiturates stimulate liver microsomal enzymes
and interact with many different drugs.
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Antianxiety Agents
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Nonbenzodiazepine-Nonbarbiturate
Sedative-Hypnotics
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Chloral hydrate is an expensive, oral drug that has a
rapid onset and fairly short duration of action.
Gastric irritation occurs and can be minimized by mixing
it with food or milk.
The liquid dose form has a disagreeable odor and taste
and can be mixed with fruit juice.
Psychologic and physical dependence can occur with
long-term use of this drug.
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Antianxiety Agents
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Nonbenzodiazepine Benzodiazepine
Receptor Agonists
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These are the latest group of drugs used to treat
insomnia.
They are not benzodiazepines but appear to bind
to benzodiazepine receptors and decrease sleep
latency. They appear to have little effect on the
sleep cycle.
Because they have the potential to cause physical
and psychologic dependence, these drugs are
controlled substances.
These drugs have the ability to cause daytime
sedation and impair driving the morning after
nighttime administration.
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Antianxiety Agents
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Melatonin Receptor Agonists
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Ramelteon was recently approved by the FDA
to treat insomnia that is characterized by
difficulty falling asleep.
 It is highly selective for melatonin receptors.
 It is not a controlled substance.
 Adverse effects do include somnolence and
dizziness.
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Antianxiety Agents
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Centrally Acting Muscle Relaxants
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They exert their effects on the CNS to produce
skeletal muscle relaxation.
They are used in treating back and muscle
pain and in patients with muscle spasms due
to a car accident.
Common side effects include GI upset,
sedation, and dizziness.
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