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Last reviewed on RxList: 10/28/2019
Alfenta Side Effects Center

Last reviewed on RxList 10/28/2019

What Is Alfenta?

Alfenta (alfentanil hydrochloride) Injection is an opioid analgesic used before and/or during surgery. Alfenta is available in generic form.

What Are Side Effects of Alfenta?

Common side effects of Alfenta include:

Dosage for Alfenta

The dosage of Alfenta should be individualized for each patient according to body weight, physical status, underlying condition, use of other drugs, and type and duration of surgical procedure and anesthesia.

What Drugs, Substances, or Supplements Interact with Alfenta?

Alfenta may interact with:

  • barbiturates,
  • tranquilizers,
  • opioids,
  • inhalation general anesthetics, or
  • cimetidine

Tell your doctor all medications and supplements you use.

Alfenta During Pregnancy and Breastfeeding

During pregnancy, Alfenta should be used only if prescribed. Caution should be used if nursing; consult your doctor before breastfeeding. Withdrawal symptoms may occur if you suddenly stop taking this medication.

Additional Information

Our Alfenta (alfentanil hydrochloride) Injection 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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Alfenta Professional Information


The following serious adverse reactions are described, or described in greater detail, in other sections:

  • Addiction, Abuse, and Misuse [see WARNINGS AND PRECAUTIONS]
  • Life-Threatening Respiratory Depression [seeWARNINGS AND PRECAUTIONS]
  • Muscle Rigidity and Skeletal Muscle Movement [seeWARNINGS AND PRECAUTIONS]
  • Interactions with Benzodiazepines and CNS Depressants [see WARNINGS AND PRECAUTIONS]
  • Serotonin Syndrome [seeWARNINGS AND PRECAUTIONS]
  • Bradycardia [see WARNINGS AND PRECAUTIONS]
  • Gastrointestinal Adverse Reactions [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 following adverse reaction information is derived from controlled and open clinical trials in 785 patients who received intravenous Alfentanil HCl Injection during induction and maintenance of general anesthesia. The controlled trials included treatment comparisons with fentanyl, thiopental sodium, enflurane, saline placebo and halothane. The incidence of certain side effects is influenced by the type of use, e.g., chest wall rigidity has a higher reported incidence in clinical trials of Alfentanil HCl Injection induction, and by the type of surgery, e.g., nausea and vomiting have a higher reported incidence in patients undergoing gynecologic surgery. The overall reports of nausea and vomiting with alfentanil were comparable to fentanyl.

Incidence Greater than 1% - Probably Causally Related (Derived from clinical trials)

Gastrointestinal: Nausea (28%), vomiting (18%)

Cardiovascular: Arrhythmia, bradycardia (14%), hypertension (18%), hypotension (10%), tachycardia (12%)

Musculoskeletal: Chest wall rigidity (17%), skeletal muscle movements*

Respiratory: Apnea*, postoperative respiratory depression

Central Nervous System: Blurred vision, dizziness*, sleepiness/postoperative sedation

*Incidence 3% to 9%; all others 1% to 3%

Incidence Less than 1% -Probably Causally Related (Derived from clinical trials)

Adverse events reported in post-marketing surveillance, not seen in clinical trials, are italicized.

Body as a whole: Anaphylaxis

Central Nervous System: Headache*, myoclonic movements, postoperative confusion*, postoperative euphoria*, shivering*

Dermatological: Itching*, urticaria*

Injection Site: Pain*

Musculoskeletal: Skeletal muscle rigidity of neck and extremities

Respiratory: Bronchospasm, hypercarbia*, laryngospasm*

*Incidence 0.3% to 1%

Postmarketing Experience

The following adverse reactions have been identified during post approval use of alfentanil. 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.

Serotonin syndrome: Cases of serotonin syndrome, a potentially life-threatening condition, have been reported during concomitant use of opioids with serotonergic drugs.

Adrenal insufficiency: Cases of adrenal insufficiency have been reported with opioid use, more often following greater than one month of use. Anaphylaxis: Anaphylaxis has been reported with ingredients contained in Alfentanil HCl Injection.

Androgen deficiency: Cases of androgen deficiency have occurred with chronic use of opioids [see CLINICAL PHARMACOLOGY].

The adverse experience profile from 696 patients receiving alfentanil for Monitored Anesthesia Care (MAC) is similar to the profile established with alfentanil during general anesthesia. Respiratory events reported during MAC included hypoxia, apnea, and bradypnea. Other adverse events reported by patients receiving alfentanil for MAC, in order of decreasing frequency, were nausea, hypotension, vomiting, pruritus, confusion, somnolence and agitation.

Read the entire FDA prescribing information for Alfenta (Alfentanil for Injection)


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Related Resources for Alfenta

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

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