Brand Names and Generic Names
Commonly encountered anxiolytic and hypnotic agents by generic and brand name:
- Benzodiazepine (as Anxiolytic-Hypnotics)
- alprazolam (Xanax)
- chlordiazepoxide (Librium)
- clonazepam (Klonopin)
- diazepam (Valium)
- lorazepam (Ativan)
- oxazepam (Serax)
- triazolam (Halcion)
- Barbiturates (as Anxiolytic-Hypnotics)
- amobarbital (Amytal sodium)
- butabarbital (Butisol)
- pentobarbital (Nembutal)
- phenobarbital (Luminal)
- Other Anxiolytic-Hypnotic Drugs
- buspirone
- diphenhydramine (Benadryl)
- meprobamate (Miltown)
- promethazine (Phenergan)
- zolpidem (Ambien)
Manifestation Spotlight: Anxiety, Sedation, and Hypnosis
Anxiety is tension, nervousness, and apprehension, an unpleasant reaction to a real or imagined stimulus, carried by sympathetic responses like fast heartbeat, rapid breathing, flushing, and sweating. It can be mild, moderate, or severe. Sedation is the loss of awareness and reaction to the environment, which can be desirable for a restless or irritable patient or before surgery. Hypnosis is further CNS depression and sleep, usually from extreme sedation, where the person no longer senses or reacts to incoming stimuli.
Benzodiazepines Used as Anxiolytic-Hypnotics
The most frequently used anxiolytics. They lyse anxiety without much sedation and are less likely to cause physical dependence.
Therapeutic Action
Acting on the limbic system and the reticular activating system (RAS), they make gamma-aminobutyric acid (GABA) more effective at interfering with neuron firing. GABA stabilizes the postsynaptic cell, producing an anxiolytic effect at a dose lower than what is needed for sedation and hypnosis. The exact mechanism is not fully understood.
Indications
Anxiety disorders, alcohol withdrawal, hyperexcitability and agitation, and preoperative relief of anxiety and tension to aid balanced anesthesia.
Children respond unpredictably and may become aggressive, tearful, and irritable, so use in this group is a challenge. Only clonazepam, clorazepate, and diazepam have established pediatric dosages, and dried secretions and their effect on breathing must always be assessed carefully. (Age-group cautions for adults and older adults are shared with barbiturates and consolidated under Nursing Considerations below.)
Pharmacokinetics
| Route | Onset | Peak | Duration |
|---|---|---|---|
| Oral | 30-60 min | 1-2 h | 3 h |
| IM | 15-30 min | 30-45 min | 3 h |
| IV | 1-5 min | 30 min | 15-60 min |
| Rectal | Rapid | 1.5 h | 3 h |
| Half-life (T1/2) | Metabolism | Excretion |
|---|---|---|
| 20-80 h | Liver | Urine |
Contraindications and Cautions
Allergy to benzodiazepines (prevent severe hypersensitivity). Psychosis can be worsened by sedation. Acute narrow-angle glaucoma, shock, coma, and acute alcoholic intoxication can be worsened by the drugs' depressant effects. In pregnancy, first-trimester use is associated with cleft lip or palate, inguinal hernia, cardiac defects, microcephaly, and pyloric stenosis, and neonatal withdrawal syndrome may follow. Lactation risks neonatal sedation. The elderly and debilitated may react unpredictably. Renal or hepatic dysfunction can alter metabolism and excretion, leading to direct toxicity.
Adverse Effects
CNS: sedation, drowsiness, depression, lethargy, blurred vision, headache, apathy, light-headedness, amnesia, confusion, and mild paradoxical excitatory reactions in the first 2 weeks of therapy. CV: hypotension, hypertension, arrhythmias, palpitations. GI: dry mouth, constipation, nausea, vomiting, elevated liver enzymes. GU: urinary retention and hesitancy, loss of libido, changes in sexual function. Hematological: blood dyscrasias, anemia. Injection sites can develop phlebitis, local reactions, and thrombosis. Abrupt cessation causes a withdrawal syndrome of nausea, headache, vertigo, malaise, and nightmares.
Interactions
Alcohol and other CNS depressants increase the risk of CNS depression. Cimetidine, oral contraceptives, and disulfiram increase benzodiazepine effects. Theophylline and ranitidine decrease benzodiazepine effects. Flumazenil is the reversal agent for benzodiazepines, but it is not used routinely: in a benzodiazepine-tolerant patient it can precipitate acute withdrawal, seizures, and dysrhythmias, so it is reserved for selected cases and ideally given with toxicology input (StatPearls).
Barbiturates Used as Anxiolytic-Hypnotics
Once the sedative-hypnotics of choice, now largely replaced by newer anxiolytics because of high addiction and dependency risk.
Therapeutic Action
General CNS depressants that inhibit neuronal impulse conduction in the ascending RAS, depress the cerebral cortex, alter cerebellar function, and depress motor output, producing sedation, hypnosis, anesthesia, and even coma.
Indications
Anxiety, sedation, insomnia, paresthesia, and seizures. Parenteral forms may treat acute manic reactions.
Barbiturates have established pediatric dosages but must be used cautiously because children often respond unexpectedly, may become aggressive, tearful, and irritable, and need careful assessment of dried secretions and breathing. (Adult and older-adult cautions are shared and consolidated under Nursing Considerations below.)
Pharmacokinetics
| Route | Onset | Peak | Duration |
|---|---|---|---|
| Oral | 15 min | 30-60 min | 10-16 h |
| IM, subcutaneous | – | 10-30 min | 4-6 h |
| IV | Up 10 15 min | 5 min | 4-6 h |
| Half-life (T1/2) | Metabolism | Excretion |
|---|---|---|
| 79 h | Liver | Urine |
Contraindications and Cautions
Allergy to barbiturates (prevent severe hypersensitivity). A history of addiction to sedative-hypnotic drugs matters because barbiturates are more addicting than most other anxiolytics. Latent or manifest euphoria may be worsened. Marked hepatic impairment or nephritis can alter metabolism and excretion. Respiratory distress and dysfunction are worsened by CNS depression. Pregnancy is associated with congenital abnormalities, and lactation risks the infant. Acute or chronic pain can produce paradoxical excitement that masks other symptoms. In a seizure disorder, abrupt withdrawal can precipitate status epilepticus. Chronic hepatic, cardiac, and respiratory disease can be worsened by the drugs' depressive effects.
Adverse Effects
CNS: drowsiness, somnolence, lethargy, ataxia, vertigo, a "hangover" feeling, abnormal thinking, paradoxical excitement, anxiety, hallucinations. CV: bradycardia, hypotension, syncope. Respiratory: serious hypoventilation and respiratory depression. Hypersensitivity reactions: rash, serum sickness, Stevens-Johnson syndrome. Physical tolerance and psychological dependence develop.
Interactions
Alcohol and other CNS depressants (antihistamines, tranquilizers) increase the risk of CNS depression. Barbiturates alter the response to phenytoin. MAO inhibitors increase serum levels of barbiturates. Through enzyme induction, barbiturates reduce the effectiveness of oral anticoagulants, digoxin, corticosteroids, tricyclic antidepressants (TCAs), oral contraceptives, acetaminophen, metronidazole, and carbamazepine.
Nursing Considerations
In September 2020 the FDA required an updated boxed warning across the entire benzodiazepine class for the risk of abuse, misuse, addiction, physical dependence, and withdrawal. Physical dependence can develop in just days to weeks of steady use, even at prescribed doses, and stopping abruptly or tapering too fast can trigger withdrawal reactions, including life-threatening seizures (FDA). This is why these drugs are short-term tools and are tapered, never stopped cold.
Across both classes, the same age-group cautions apply to adults and older adults. For adults, stress that drugs for insomnia are short-term only, push nondrug sleep measures first (a set bedtime, warm bath, back rub), and warn against driving, sports, and legal decisions while taking them; evaluate liver function before and during therapy, and do not use these drugs in pregnant or lactating women. Older adults are more prone to adverse effects like hallucinations and sedation, so reduce the dose, monitor closely for toxicity, watch liver and renal function, and encourage nondrug measures to reduce anxiety.
Nursing Assessment
Screen for the listed cautions and contraindications (drug allergies, hepatorenal disease, psychosis, glaucoma, seizure disorders) to prevent complications. Do a full physical for baseline data and to catch adverse effects. Monitor labs (renal and liver function tests, CBC) to track effectiveness and catch developing complications early.
Nursing Diagnoses
Disturbed thought processes and sensory perception related to CNS effects. Disturbed sleep pattern related to CNS effects. Risk for injury related to CNS effects. With barbiturates, impaired gas exchange related to respiratory depression.
Implementation with Rationale
Give IV benzodiazepines slowly to prevent respiratory depression, hypotension, and cardiac complications. Give IV barbiturates slowly because rapid administration may cause cardiac problems. Do not mix IV drugs in solution with any other drug, to avoid interactions. Keep patients who receive parenteral benzodiazepines in bed for at least 3 hours for safety. With barbiturates, taper the dose as ordered because abrupt withdrawal can precipitate seizures. Monitor response through vital signs, weight, serum electrolytes, and hydration, and follow hepatic and renal function and CBC on long-term therapy so you can taper and discontinue if dysfunction appears. Provide comfort measures (small frequent meals, bathroom access, orientation) and safety measures (adequate lighting, raised side rails) to prevent injury, and teach the patient the regimen to promote compliance.
Evaluation
Monitor response to therapy (controlled anxiety, sleep). Monitor for adverse effects (hypotension, blood dyscrasias, dependence, hepatorenal dysfunction). Confirm understanding by having the patient name the drug, its indication, and the adverse effects to watch for, and monitor compliance.
Frequently Asked Questions
What is the difference between an anxiolytic, a sedative, and a hypnotic?
It is mostly a matter of dose. The same CNS-depressant drug blunts tension and fear at low doses (anxiolytic), calms and reduces awareness at higher doses (sedative), and produces sleep at higher doses still (hypnotic).
Why are benzodiazepines preferred over barbiturates?
Benzodiazepines relieve anxiety with less sedation and less physical dependence than barbiturates, and they have a wider safety margin in overdose. Barbiturates carry high addiction risk and dangerous respiratory depression, so they have largely been replaced for routine anxiety and insomnia.
What is the reversal agent for a benzodiazepine overdose?
Flumazenil. It competitively blocks the benzodiazepine receptor, but it is not used routinely: in dependent patients it can precipitate withdrawal, seizures, and dysrhythmias, so it is reserved for selected cases.
Why can't benzodiazepines be stopped abruptly?
Physical dependence can develop within days to weeks, even at prescribed doses. Stopping suddenly or tapering too quickly can cause withdrawal, including nausea, tremor, and life-threatening seizures, which is why the FDA carries a class-wide boxed warning and why these drugs are tapered.
Are these drugs meant for long-term use?
No. They are short-term tools for insomnia and anxiety. Nondrug measures (a set bedtime, a warm bath, reducing stimulants) are pushed first, and prolonged use raises the risk of tolerance, dependence, and oversedation.
Which patients are most sensitive to oversedation?
Older and debilitated adults react more strongly and unpredictably, with a higher risk of hallucinations, falls, and confusion, so doses are reduced and they are monitored closely. Children may also respond paradoxically with agitation, and anyone with hepatic or renal impairment clears the drug more slowly.