Halcion Side Effects Center

Last updated on RxList: 2/3/2023
Halcion Side Effects Center

What Is Halcion?

Halcion (triazolam) is a benzodiazepine used to treat insomnia symptoms, such as trouble falling or staying asleep. Halcion is available in generic form.

What Are Side Effects of Halcion?

Halcion may cause serious side effects including:

  • unusual changes in mood or behavior,
  • confusion,
  • memory loss (amnesia),
  • hallucinations,
  • depression, and
  • suicidal thoughts

Get medical help right away, if you have any of the symptoms listed above.

Common side effects of Halcion include:

  • dizziness,
  • tiredness,
  • daytime drowsiness (or during hours when you are not normally sleeping),
  • loss of coordination,
  • headache,
  • depression,
  • memory problems,
  • numbness or tingly feeling,
  • nervousness,
  • excitability,
  • irritability,
  • changes in menstrual periods,
  • itching,
  • increased or decreased interest in sex, or
  • blurred vision.

Tell your doctor if you have serious side effects of Halcion including:

  • memory loss, or
  • mental/mood/behavior changes (such as new or worsening depression, abnormal thoughts, thoughts of suicide, hallucinations, confusion, agitation, aggressive behavior, or anxiety).

Rarely, after taking Halcion, people have gotten out of bed and driven vehicles while not fully awake ("sleep-driving"). People have also sleepwalked, prepared/eaten food, made phone calls, or had sex while not fully awake. Often, these people do not remember these events. This problem can be dangerous to you or to others. If you find out that you have done any of these activities after taking Halcion, tell your doctor right away.

Seek medical care or call 911 at once if you have the following serious side effects:

  • Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
  • Serious heart symptoms such as fast, irregular, or pounding heartbeats; fluttering in your chest; shortness of breath; and sudden dizziness, lightheartedness, or passing out;
  • Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors.

This document does not contain all possible side effects and others may occur. Check with your physician for additional information about side effects.

Dosage for Halcion

The recommended dose of Halcion for most adults is 0.25 mg before retiring.

What Drugs, Substances, or Supplements Interact with Halcion?

Halcion may interact with birth control pills, cyclosporine, grapefruit juice, ranitidine, antibiotics, antidepressants, ergotamine, heart medications, or other medicines that make you sleepy (such as cold or allergy medicine, other sedatives, narcotic pain medicine, sleeping pills, muscle relaxers, and medicine for seizures, depression, or anxiety). Tell your doctor all medications you use.

Halcion During Pregnancy and Breastfeeding

Halcion must not be used during pregnancy. Other medications in this class cause birth defects when used in the first three months of pregnancy. Other medications in this class also cause drowsiness, feeding problems, and liver problems in newborns when used at or near the time of delivery, or withdrawal symptoms in newborns when used during pregnancy. Use birth control while taking this drug. Based on information from related drugs, Halcion may pass into breast milk and may have undesirable effects on a nursing infant. Breastfeeding while using this drug is not recommended. Withdrawal symptoms may occur if this drug is abruptly stopped.

Additional Information

Our Halcion (triazolam) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


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Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Triazolam can slow or stop your breathing, especially if you have recently used an opioid medication or alcohol. A person caring for you should seek emergency medical attention if you have slow breathing with long pauses, blue colored lips, or if you are hard to wake up.

Call your doctor at once if you have:

  • daytime anxiety;
  • unusual changes in mood or behavior;
  • confusion, memory loss, agitation, hallucinations; or
  • depression, suicidal thoughts.

Some people using triazolam have engaged in activity such as driving, eating, walking, making phone calls, or having sex and later having no memory of the activity. Tell your doctor if this happens to you.

Drowsiness or dizziness may last longer in older adults. Use caution to avoid falling or accidental injury.

Common side effects may include:

  • drowsiness;
  • loss of coordination;
  • dizziness; or
  • feeling light-headed.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


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The following serious adverse reactions are discussed in greater detail in other sections:

  • Risks from Concomitant Use with Opioids [see WARNINGS AND PRECAUTIONS]
  • Abuse, Misuse, and Addiction [see WARNINGS AND PRECAUTIONS]
  • Dependence and Withdrawal Reactions [see WARNINGS AND PRECAUTIONS]
  • Persistent or Worsening Insomnia [see WARNINGS AND PRECAUTIONS]
  • “Sleep-driving” and Other Complex Behaviors [see WARNINGS AND PRECAUTIONS]
  • Central Nervous System Manifestations [see WARNINGS AND PRECAUTIONS]
  • Effects on Driving and Operating Heavy Machinery [see WARNINGS AND PRECAUTIONS]
  • Patients with Depression [see WARNINGS AND PRECAUTIONS]
  • Neonatal Sedation and Withdrawal Syndrome [see WARNINGS AND PRECAUTIONS]
  • Compromised Respiratory Function [see WARNINGS AND PRECAUTIONS]

Clinical Trials Experience

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

The incidences cited below are estimates of clinical reactions among 1003 subjects who participated in the short term (duration of 1 to 42 days) placebo-controlled clinical trials of Halcion.

Adverse reactions leading to discontinuation in two multi-dose placebo controlled clinical trials include coordination disorders, drowsiness, grogginess, somnolence, depression, restlessness, dizziness, lightheadedness, headache, nausea, visual disturbance, nervousness, abdominal distress, bladder trouble, aching limbs, backache, and blepharitis.

Table 1: Common Adverse Drug Reactions in 1% or More of Halcion-Treated Subjects (and Greater than Placebo) Reported in Placebo-Controlled Clinical Trials

Event Halcion
(N=1003) % Patients Reporting
(N=997) % Patients Reporting
Central Nervous System
Drowsiness 14.0 6.4
Headache 9.7 8.4
Dizziness 7.8 3.1
Nervousness 5.2 4.5
Light-headedness 4.9 0.9
Coordination disorders/ataxia 4.6 0.8
Nausea/vomiting 4.6 3.7

In addition to the common reactions enumerated above in Table1, the following adverse reactions have been reported at an incidence of 0.9% to 0.5%: euphoria, tachycardia, tiredness, confusional states/memory impairment, cramps/pain, depression, and visual disturbances.

Adverse reactions reported at an incidence less than 0.5% include: constipation, taste alterations, diarrhea, dry mouth, dermatitis/allergy, dreaming/nightmares, insomnia, paresthesia, tinnitus, dysesthesia, weakness, congestion, and death from hepatic failure in a patient also receiving diuretic drugs.

Postmarketing Experience

The following adverse reactions have been identified during post-approval use of Halcion. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

General disorders and administration site conditions: Paradoxical drug reaction, chest pain and fatigue

Gastrointestinal disorders: Tongue discomfort, glossitis, stomatitis

Hepatobiliary disorders: Jaundice

Injury, poisoning and procedural complications: Fall

Metabolism and nutrition disorders: Anorexia

Nervous system disorders: Anterograde amnesia, altered state of consciousness, dystonia, sedation, syncope, dysarthria and muscle spasticity

Psychiatric disorders: Confusional state (disorientation, derealisation, depersonalization), mania, agitation, restlessness, irritability, sleep disorder and libido disorder, hallucination, delusion, aggression, somnambulism, and abnormal behavior

Renal and urinary disorders: Urinary retention and urinary incontinence

Reproductive system and breast disorders: Menstruation irregular

Skin and subcutaneous tissue disorders: Pruritis


Drugs Having Clinically Important Interactions With Halcion

Table 2 includes clinically significant drug interactions with Halcion [see CLINICAL PHARMACOLOGY].

Table 2: Clinically Important Drug Interactions with Halcion

Clinical implication The concomitant use of benzodiazepines and opioids increases the risk of respiratory depression because of actions at different receptor sites in the CNS that control respiration. Benzodiazepines interact at GABAa sites and opioids interact primarily at mu receptors. When benzodiazepines and opioids are combined, the potential for benzodiazepines to significantly worsen opioid-related respiratory depression exists.
Prevention or management Limit dosage and duration of concomitant use of Halcion and opioids, and monitor patients closely for respiratory depression and sedation [see WARNINGS AND PRECAUTIONS].
CNS Depressants
Clinical implication Triazolam produces additive CNS depressant effects when co-administered with other CNS depressants.
Prevention or management Limit dosage and duration of Halcion during concomitant use with CNS depressants.
Strong Inhibitors of CYP 3A
Clinical implication Concomitant use of Halcion with strong CYP3A inhibitors has a profound effect on the clearance of Halcion, resulting in increased concentrations of triazolam and increased risk of adverse reactions [see CLINICAL PHARMACOLOGY].
Prevention or management Do not administer Halcion with a strong CYP3A4 inhibitor [see Contraindications (4), WARNINGS AND PRECAUTIONS].
Moderate and Weak Inhibitors of CYP 3A
Clinical implication Concomitant use of Halcion with moderate or weak inhibitors of CYP3A inhibitors may increase the concentrations of Halcion, resulting in increased risk of adverse reactions [see CLINICAL PHARMACOLOGY].
Prevention or management Use with caution and consider appropriate dose reduction of HALCION when coadministered with moderate and weak CYP3A inhibitors [see WARNINGS AND PRECAUTIONS].
Strong Inducers of CYP 3A
Clinical implication Coadministration of triazolam with strong inducers of CYP3A4 can significantly decrease the plasma concentration of triazolam and may decrease effectiveness of triazolam.
Prevention or management Caution is recommended during coadministration of Halcion with strong inducers of CYP3A4.
Interactions Based on Experience with Other Benzodiazepines or in vitro Studies with Triazolam
Clinical implication Available data from clinical studies of benzodiazepines other than triazolam, from in vitro studies with triazolam, or from in vitro studies with benzodiazepines other than triazolam suggest a possible drug interaction with triazolam [see CLINICAL PHARMACOLOGY].
Prevention or management Caution is recommended during coadministration of Halcion with any of these drugs. [see WARNINGS AND PRECAUTIONS].

Drug Abuse And Dependence

Controlled Substance

Halcion contains triazolam, a Schedule IV controlled substance.


Halcion is a benzodiazepine and a CNS depressant with a potential for abuse and addiction. Abuse is the intentional, non-therapeutic use of a drug, even once, for its desirable psychological or physiological effects. Misuse is the intentional use, for therapeutic purposes, of a drug by an individual in a way other than prescribed by a health care provider or for whom it was not prescribed. Drug addiction is a cluster of behavioral, cognitive, and physiological phenomena that may include a strong desire to take the drug, difficulties in controlling drug use (e.g., continuing drug use despite harmful consequences, giving a higher priority to drug use than other activities and obligations), and possible tolerance or physical dependence. Even taking benzodiazepines as prescribed may put patients at risk for abuse and misuse of their medication. Abuse and misuse of benzodiazepines may lead to addiction.

Abuse and misuse of benzodiazepines often (but not always) involve the use of doses greater than the maximum recommended dosage and commonly involve concomitant use of other medications, alcohol, and/or illicit substances, which is associated with an increased frequency of serious adverse outcomes, including respiratory depression, overdose, or death. Benzodiazepines are often sought by individuals who abuse drugs and other substances, and by individuals with addictive disorders [see WARNINGS AND PRECAUTIONS].

The following adverse reactions have occurred with benzodiazepine abuse and/or misuse: abdominal pain, amnesia, anorexia, anxiety, aggression, ataxia, blurred vision, confusion, depression, disinhibition, disorientation, dizziness, euphoria, impaired concentration and memory, indigestion, irritability, muscle pain, slurred speech, tremors, and vertigo.

The following severe adverse reactions have occurred with benzodiazepine abuse and/or misuse: delirium, paranoia, suicidal ideation and behavior, seizures, coma, breathing difficulty, and death. Death is more often associated with polysubstance use (especially benzodiazepines with other CNS depressants such as opioids and alcohol).


Physical Dependence

Halcion may produce physical dependence from continued therapy. Physical dependence is a state that develops as a result of physiological adaptation in response to repeated drug use, manifested by withdrawal signs and symptoms after abrupt discontinuation or a significant dose reduction of a drug. Abrupt discontinuation or rapid dosage reduction of benzodiazepines or administration of flumazenil, a benzodiazepine antagonist, may precipitate acute withdrawal reactions, including seizures, which can be life-threatening. Patients at an increased risk of withdrawal adverse reactions after benzodiazepine discontinuation or rapid dosage reduction include those who take higher dosages (i.e., higher and/or more frequent doses) and those who have had longer durations of use [see WARNINGS AND PRECAUTIONS].

To reduce the risk of withdrawal reactions, use a gradual taper to discontinue Halcion or reduce the dosage [see DOSAGE AND ADMINISTRATION, WARNINGS AND PRECAUTIONS].

Acute Withdrawal Signs And Symptoms

Acute withdrawal signs and symptoms associated with benzodiazepines have included abnormal involuntary movements, anxiety, blurred vision, depersonalization, depression, derealization, dizziness, fatigue, gastrointestinal adverse reactions (e.g., nausea, vomiting, diarrhea, weight loss, decreased appetite), headache, hyperacusis, hypertension, irritability, insomnia, memory impairment, muscle pain and stiffness, panic attacks, photophobia, restlessness, tachycardia, and tremor. More severe acute withdrawal signs and symptoms, including life-threatening reactions, have included catatonia, convulsions, delirium tremens, depression, hallucinations, mania, psychosis, seizures, and suicidality.

Protracted Withdrawal Syndrome

Protracted withdrawal syndrome associated with benzodiazepines is characterized by anxiety, cognitive impairment, depression, insomnia, formication, motor symptoms (e.g., weakness, tremor, muscle twitches), paresthesia, and tinnitus that persists beyond 4 to 6 weeks after initial benzodiazepine withdrawal. Protracted withdrawal symptoms may last weeks to more than 12 months. As a result, there may be difficulty in differentiating withdrawal symptoms from potential re-emergence or continuation of symptoms for which the benzodiazepine was being used.


Tolerance to Halcion may develop from continued therapy. Tolerance is a physiological state characterized by a reduced response to a drug after repeated administration (i.e., a higher dose of a drug is required to produce the same effect that was once obtained at a lower dose). Tolerance to the therapeutic effect of Halcion may develop; however, little tolerance develops to the amnestic reactions and other cognitive impairments caused by benzodiazepines.

Read the entire FDA prescribing information for Halcion (Triazolam)

© Halcion Patient Information is supplied by Cerner Multum, Inc. and Halcion Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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