Skip to main content

Halcion Side Effects

Generic name: triazolam

Medically reviewed by Last updated on Mar 18, 2023.

Note: This document contains side effect information about triazolam. Some dosage forms listed on this page may not apply to the brand name Halcion.


More frequent side effects include: dizziness, insomnia, rebound insomnia, headache, and irritability. Continue reading for a comprehensive list of adverse effects.

Applies to triazolam: oral tablet.


Oral route (Tablet)

Risks From Concomitant Use With Opioids; Abuse, Misuse, and Addiction; and Dependence and Withdrawal ReactionsConcomitant use of benzodiazepines and opioids may result in profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing of these drugs in patients for whom alternative treatment options are inadequate. Limit dosages and durations to the minimum required. Follow patients for signs and symptoms of respiratory depression and sedation.The use of benzodiazepines, including triazolam, exposes users to risks of abuse, misuse, and addiction, which can lead to overdose or death. Abuse and misuse of benzodiazepines commonly involve concomitant use of other medications, alcohol, and/or illicit substances, which is associated with an increased frequency of serious adverse outcomes. Before prescribing triazolam and throughout treatment, assess each patient’s risk for abuse, misuse, and addiction.The continued use of benzodiazepines, including triazolam, may lead to clinically significant physical dependence. The risks of dependence and withdrawal increase with longer treatment duration and higher daily dose. Abrupt discontinuation or rapid dosage reduction of triazolam after continued use may precipitate acute withdrawal reactions, which can be life-threatening. To reduce the risk of withdrawal reactions, use a gradual taper to discontinue triazolam or reduce the dosage.

Serious side effects of Halcion

Along with its needed effects, triazolam (the active ingredient contained in Halcion) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking triazolam:

Less common

  • Shakiness and unsteady walk
  • unsteadiness, trembling, or other problems with muscle control or coordination


  • Being forgetful
  • burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings
  • continuing ringing or buzzing or other unexplained noise in the ears
  • discouragement
  • false or unusual sense of well-being
  • fast, pounding, or irregular heartbeat or pulse
  • feeling sad or empty
  • hearing loss
  • irritability
  • lack of appetite
  • loss of interest or pleasure
  • nightmares
  • tiredness
  • trouble concentrating
  • trouble sleeping

Incidence not known

  • Actions that are out of control
  • aggressiveness
  • anxiety
  • changes in patterns and rhythms of speech
  • chest pain
  • chills
  • clay-colored stools
  • confusion about identity, place, and time
  • dark urine
  • decrease in frequency of urination
  • decrease in urine volume
  • difficulty in passing urine (dribbling)
  • dizziness
  • drowsiness
  • dry mouth
  • environment seems unreal
  • fainting
  • falling
  • false beliefs that cannot be changed by facts
  • feeling of unreality
  • fever
  • headache
  • hyperventilation
  • inability to move the eyes
  • increased blinking or spasms of the eyelid
  • increased muscle spasm
  • irregular heartbeat
  • loss of bladder control
  • loss of memory
  • nausea
  • nervousness
  • painful urination
  • problems with memory
  • rash
  • relaxed and calm feeling
  • restlessness
  • seeing, hearing, or feeling things that are not there
  • sense of detachment from self or body
  • sleep walking
  • sleepiness
  • slurred speech
  • sticking out of tongue
  • stomach pain
  • talking, feeling, and acting with excitement
  • trouble breathing, speaking, or swallowing
  • uncontrolled twisting movements of the neck, trunk, arms, or legs
  • unpleasant breath odor
  • unusual excitement, nervousness, restlessness, or irritability
  • unusual facial expressions
  • unusual tiredness or weakness
  • vomiting of blood
  • yellow eyes or skin

Get emergency help immediately if any of the following symptoms of overdose occur while taking triazolam:

Symptoms of overdose

  • Agitation
  • change in consciousness
  • changes in patterns and rhythms of speech
  • confusion
  • irregular, fast or slow, or shallow breathing
  • loss of consciousness
  • loss of strength or energy
  • nightmares
  • mood or mental changes
  • pale or blue lips, fingernails, or skin
  • shakiness and unsteady walk
  • slurred speech
  • talkativeness
  • trouble speaking
  • unsteadiness, trembling, or other problems with muscle control or coordination
  • unusual drowsiness, dullness, tiredness, weakness, or feeling of sluggishness
  • unusual excitement, nervousness, restlessness, or irritability

Other side effects of Halcion

Some side effects of triazolam may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

  • Lightheadedness


  • Blistering, crusting, irritation, itching, or reddening of the skin
  • change in taste, or bad, unusual, or unpleasant (after) taste
  • change in vision
  • cracked, dry, or scaly skin
  • cramps
  • diarrhea
  • difficulty having a bowel movement
  • dry mouth
  • swelling
  • weakness

Incidence not known

  • Decreased interest in sexual intercourse
  • inability to have or keep an erection
  • increase in sexual ability, desire, drive, or performance
  • increase interest in sexual intercourse
  • itching skin
  • loss in sexual ability, desire, drive, or performance
  • menstrual changes
  • redness, swelling, or soreness of the tongue
  • swelling or inflammation of the mouth
  • weight loss

For Healthcare Professionals

Applies to triazolam: oral tablet.


The most commonly reported side effects included drowsiness/sedation, dizziness/lightheadedness, headache, and ataxia.[Ref]

Nervous system

Very common (10% or more): Sedation (up to 19.4%), drowsiness (up to 14%)

Common (1% to 10%): Anterograde amnesia with appropriate/inappropriate behavior, ataxia, concentration difficulty, coordination disorders/impaired coordination, dizziness, headache, impaired equilibrium, lethargy, lightheadedness, memory impairment

Rare (0.01% to 0.1%): Dysesthesia, paresthesia, taste alterations

Frequency not reported: Amnestic symptoms, clouding of consciousness/altered state of consciousness, dysarthria, dystonia, grogginess, slurred speech, somnambulism, somnolence, syncope[Ref]

Complex behaviors, such as "sleep-driving", other behaviors such as preparing and eating food, making phone calls, or having sex, with amnesia for these events, have been reported at therapeutic doses with this medicine.[Ref]


Very common (10% or more): WBC/high power field (HPF) in urinalysis (up to 11.3%)

Common (1% to 10%): Albuminuria, red blood cells/HPF in urinalysis

Frequency not reported: Bladder trouble, incontinence, menstrual irregularities, urinary retention[Ref]


Very common (10% or more): Low eosinophil count (up to 10.2%)

Common (1% to 10%): High eosinophil count, low monocyte count, low/high basophil count, low/high lymphocyte count, low/high neutrophil count, low/high WBC count


Common (1% to 10%): High bilirubin, increased alkaline phosphatase, low/high creatinine

Frequency not reported: Anorexia[Ref]


Rebound insomnia (a worsening of sleep following cessation of therapy) has been observed and has sometimes been reported to occur in association with increased daytime anxiety.

Withdrawal symptoms have included agitation, restlessness, anxiety, insomnia, psychosis, delirium, convulsions, tremor, abdominal cramps, blurred vision, vomiting, and sweating.

Worsening of insomnia, depression, or the emergence of new thinking or behavior abnormalities, including suicidal thinking, have emerged during treatment with sedative-hypnotic drugs, including this drug. The frequency and extent to which this drug is associated with adverse behavioral effects is controversial.

One study based on the postmarketing surveillance Spontaneous Reporting System of the FDA has suggested that adverse behavioral reactions have been reported 22 to 99 times more frequently in association with triazolam (the active ingredient contained in Halcion) therapy than with temazepam therapy for insomnia. An increased frequency of adverse behavioral effects was noted to occur most frequently in elderly patients and at higher doses of this drug. The methodology of this study, however, has been questioned on the grounds that spontaneous reports of adverse effects do not necessarily correlate with the incidence of adverse effects.

Other studies and reports have concluded that little evidence exists to support the contention that this drug is associated with a greater risk of adverse behavioral effects than other benzodiazepines (including temazepam).[Ref]

Common (1% to 10%): Anxiety, nervousness

Uncommon (0.1% to 1%): Confusional states, depression, euphoria

Rare (0.01% to 0.1%): Dreaming, insomnia, nightmares

Frequency not reported: Abnormal behavior, abnormal dreams, abuse, acute rage, addiction, aggressiveness/aggression, agitation, agitational state, bizarre behavior, changes in libido, delusions, depersonalization, derealization, disorientation, disorientation in time/place, excitation, hallucinations, inappropriate behavior, irritability, libido disorder, mania, other adverse behavioral effects, paranoia, restlessness, sleep disorder/sleep disturbances, stimulation[Ref]


Common (1% to 10%): Nausea, vomiting

Rare (0.01% to 0.1%): Constipation, diarrhea, dry mouth

Frequency not reported: Abdominal distress, burning tongue, glossitis, stomatitis, tongue discomfort[Ref]


Common (1% to 10%): Tiredness

Uncommon (0.1% to 1%): Pain

Rare (0.01% to 0.1%): Tinnitus, weakness

Frequency not reported: Falling, fatigue, paradoxical reactions[Ref]


Common (1% to 10%): High AST levels

Rare (0.01% to 0.1%): Death (from hepatic failure)

Frequency not reported: Jaundice[Ref]

Death from hepatic failure has been reported in a patient also receiving diuretic drugs.[Ref]


Uncommon (0.1% to 1%): Pruritus, skin rash

Rare (0.01% to 0.1%): Dermatitis[Ref]


Uncommon (0.1% to 1%): Palpitations, tachycardia

Frequency not reported: Chest pain[Ref]


Uncommon (0.1% to 1%): Hiccups

Rare (0.01% to 0.1%): Congestion[Ref]

One study of patients with obstructive sleep apnea has suggested that this drug may increase the maximum apnea duration and lower the minimum oxygen saturation of apneic patients.[Ref]


Uncommon (0.1% to 1%): Cramps

Frequency not reported: Aching limbs, backache, increased muscle spasticity[Ref]


Uncommon (0.1% to 1%): Visual disturbances

Frequency not reported: Blepharitis[Ref]


Rare (0.01% to 0.1%): Allergy

Postmarketing reports: Anaphylactic shock, anaphylactoid reaction, allergic edema, angioneurotic edema, hypersensitivity reaction[Ref]


1. "Product Information. Halcion (triazolam)." Pharmacia and Upjohn (2001):

2. Cerner Multum, Inc. "Australian Product Information." O 0

3. Rothschild AJ "Disinhibition, amnestic reactions, and other adverse reactions secondary to triazolam: a review of the literature." J Clin Psychiatry 53 (1992): 69-79

4. Morris HH, 3d Estes ML "Traveler's amnesia. Transient global amnesia secondary to triazolam." JAMA 258 (1987): 945-6

5. Wysowski DK, Barash D "Adverse behavioral reactions attributed to triazolam in the Food and Drug Administration's Spontaneous Reporting System." Arch Intern Med 151 (1991): 2003-8

6. Andreadis NA, Schirmer RG "Use of spontaneous reporting system data." Arch Intern Med 152 (1992): 1527-9

7. Patterson WM "Triazolam withdrawal." J Clin Psychiatry 49 (1988): 369

8. Weilburg JB, Sachs G, Falk WE "Triazolam-induced brief episodes of secondary mania in a depressed patient." J Clin Psychiatry 48 (1987): 492-3

9. Schneider LS, Syapin PJ, Pawluczyk S "Seizures following triazolam withdrawal despite benzodiazepine treatment." J Clin Psychiatry 48 (1987): 418-9

10. Heritch AJ, Capwell R, Roy-Byrne PP "A case of psychosis and delirium following withdrawal from triazolam." J Clin Psychiatry 48 (1987): 168-9

11. Schogt B, Conn D "Paranoid symptoms associated with triazolam." Can J Psychiatry 30 (1985): 462-3

12. Rush CR, Higgins ST, Hughes JR, Bickel WK "A comparison of the acute behavioral effects of triazolam and temazepam in normal volunteers." Psychopharmacology (Berl) 112 (1993): 407-14

13. Sullivan RJ, Jr "Respiratory depression requiring ventilatory support following 0.5 mg of triazolam." J Am Geriatr Soc 37 (1989): 450-2

14. Berry RB, Kouchi K, Bower J, Prosise G, Light RW "Triazolam in patients with obstructive sleep apnea." Am J Respir Crit Care Med 151 (1995): 450-4

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.