April 26, 2017
Recommended Topic Related To:


"Potential drug treatments are tested on paper, in laboratories and eventually in thousands of people. But every drug that goes through this cycle “ every drug that FDA approves “ carries some risk. One of the first lines of defense against "...



Side Effects


Serious Adverse Reactions

Deaths have occurred in patients who received flumazenil in a variety of clinical settings. The majority of deaths occurred in patients with serious underlying disease or in patients who had ingested large amounts of non-benzodiazepine drugs (usually cyclic antidepressants), as part of an overdose.

Serious adverse events have occurred in all clinical settings, and convulsions are the most common serious adverse events reported. Flumazenil administration has been associated with the onset of convulsions in patients with severe hepatic impairment and in patients who are relying on benzodiazepine effects to control seizures, are physically dependent on benzodiazepines, or who have ingested large doses of other drugs (mixed-drug overdose) (see WARNINGS).

Two of the 446 patients who received flumazenil in controlled clinical trials for the management of a benzodiazepine overdose had cardiac dysrhythmias (1 ventricular tachycardia, 1 junctional tachycardia).

Adverse Events In Clinical Studies

The following adverse reactions were considered to be related to flumazenil administration (both alone and for the reversal of benzodiazepine effects) and were reported in studies involving 1875 individuals who received flumazenil in controlled trials. Adverse events most frequently associated with flumazenil alone were limited to dizziness, injection site pain, increased sweating, headache, and abnormal or blurred vision (3% to 9%).

Body as a Whole: fatigue (asthenia, malaise), headache, injection site pain*, injection site reaction (thrombophlebitis, skin abnormality, rash)

Cardiovascular System: cutaneous vasodilation (sweating, flushing, hot flushes)

Digestive System: nausea, vomiting (11%)

Nervous System: agitation (anxiety, nervousness, dry mouth, tremor, palpitations, insomnia, dyspnea, hyperventilation)*, dizziness (vertigo, ataxia) (10%), emotional lability (crying abnormal, depersonalization, euphoria, increased tears, depression, dysphoria, paranoia)

Special Senses: abnormal vision (visual field defect, diplopia), paresthesia (sensation abnormal, hypoesthesia)

All adverse reactions occurred in 1% to 3% of cases unless otherwise marked.

Observed percentage reported if greater than 9%.

The following adverse events were observed infrequently (less than 1%) in the clinical studies, but were judged as probably related to flumazenil administration and/or reversal of benzodiazepine effects:

Nervous System: confusion (difficulty concentrating, delirium), convulsions (see WARNINGS), somnolence (stupor)

Special Senses: abnormal hearing (transient hearing impairment, hyperacusis, tinnitus)

The following adverse events occurred with frequencies less than 1% in the clinical trials. Their relationship to flumazenil administration is unknown, but they are included as alerting information for the physician.

Body as a Whole: rigors, shivering

Cardiovascular System: arrhythmia (atrial, nodal, ventricular extrasystoles), bradycardia, tachycardia, hypertension, chest pain

Digestive System: hiccup

Nervous System: speech disorder (dysphonia, thick tongue)

Not included in this list is operative site pain that occurred with the same frequency in patients receiving placebo as in patients receiving flumazenil for reversal of sedation following a surgical procedure.

*indicates reaction in 3% to 9% of cases.

Additional Adverse Reactions Reported During Post-marketing Experience

The following events have been reported during postapproval use of flumazenil.

Nervous System: Fear, panic attacks in patients with a history of panic disorders.

Withdrawal symptoms may occur following rapid injection of flumazenil in patients with long-term exposure to benzodiazepines.

To report SUSPECTED ADVERSE REACTIONS, contact West-ward Pharmaceutical Corp. at 1-877- 233-2001 or the FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

Drug Abuse And Dependence

Flumazenil injection acts as a benzodiazepine antagonist, blocks the effect of benzodiazepines in animals and man, antagonizes benzodiazepine reinforcement in animal models, produces dysphoria in normal subjects, and has had no reported abuse in foreign marketing.

Although flumazenil has a benzodiazepine-like structure it does not act as a benzodiazepine agonist in man and is not a controlled substance.

Read the Romazicon (flumazenil) Side Effects Center for a complete guide to possible side effects


Interaction with central nervous system depressants other than benzodiazepines has not been specifically studied; however, no deleterious interactions were seen when flumazenil was administered after narcotics, inhalational anesthetics, muscle relaxants and muscle relaxant antagonists administered in conjunction with sedation or anesthesia.

Particular caution is necessary when using flumazenil in cases of mixed drug overdosage since the toxic effects (such as convulsions and cardiac dysrhythmias) of other drugs taken in overdose (especially cyclic antidepressants) may emerge with the reversal of the benzodiazepine effect by flumazenil (see WARNINGS).

The use of flumazenil is not recommended in epileptic patients who have been receiving benzodiazepine treatment for a prolonged period. Although flumazenil exerts a slight intrinsic anticonvulsant effect, its abrupt suppression of the protective effect of a benzodiazepine agonist can give rise to convulsions in epileptic patients.

Flumazenil blocks the central effects of benzodiazepines by competitive interaction at the receptor level. The effects of nonbenzodiazepine agonists at benzodiazepine receptors, such as zopiclone, triazolopyridazines and others, are also blocked by flumazenil.

The pharmacokinetics of benzodiazepines are unaltered in the presence of flumazenil and vice versa.

There is no pharmacokinetic interaction between ethanol and flumazenil.

Use In Ambulatory Patients

The effects of flumazenil may wear off before a long-acting benzodiazepine is completely cleared from the body. In general, if a patient shows no signs of sedation within 2 hours after a 1-mg dose of flumazenil, serious resedation at a later time is unlikely. An adequate period of observation must be provided for any patient in whom either long-acting benzodiazepines (such as diazepam) or large doses of short-acting benzodiazepines (such as > 10 mg of midazolam) have been used (see Individualization Of Dosage).

Because of the increased risk of adverse reactions in patients who have been taking benzodiazepines on a regular basis, it is particularly important that physicians query patients or their guardians carefully about benzodiazepine, alcohol and sedative use as part of the history prior to any procedure in which the use of flumazenil is planned (see PRECAUTIONS: Use in Drug- and Alcohol-Dependent Patients ).

Laboratory Tests

No specific laboratory tests are recommended to follow the patient's response or to identify possible adverse reactions.

Drug/Laboratory Test Interactions

The possible interaction of flumazenil with commonly used laboratory tests has not been evaluated.

This monograph has been modified to include the generic and brand name in many instances.

Last reviewed on RxList: 4/13/2016

Side Effects

Report Problems to the Food and Drug Administration


You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Women's Health

Find out what women really need.

Related Drugs
Health Resources
Use Pill Finder Find it Now See Interactions

Pill Identifier on RxList

  • quick, easy,
    pill identification

Find a Local Pharmacy

  • including 24 hour, pharmacies

Interaction Checker

  • Check potential drug interactions
Search the Medical Dictionary for Health Definitions & Medical Abbreviations