July 25, 2016
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Side Effects


The most common adverse reactions of opioids are respiratory depression and skeletal muscle rigidity, particularly of the truncal muscles. ALFENTA (alfenta (alfenta (alfentanil) nil) nil) may produce muscular rigidity that involves the skeletal muscles of the neck and extremities. See CLINICAL PHARMACOLOGY, WARNINGS, and PRECAUTIONS on the management of respiratory depression and skeletal muscle rigidity.

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

The following adverse reaction information is derived from controlled and open clinical trials in 785 patients who received intravenous ALFENTA (alfenta (alfenta (alfentanil) nil) nil) 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 alfenta (alfenta (alfenta (alfentanil) nil) nil) nil 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 ALFENTA (alfenta (alfenta (alfentanil) nil) nil) 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%

Drug Abuse And Dependence

ALFENTA (alfenta (alfenta (alfenta (alfentanil) nil) nil) nil hydrochloride) is a Schedule II controlled drug substance that can produce drug dependence of the morphine type and therefore has the potential for being abused.

Opioid analgesics have been associated with abuse and dependence in health care providers and others with ready access to such drugs. ALFENTA (alfenta (alfenta (alfentanil) nil) nil) should be handled accordingly.

Read the Alfenta (alfentanil for injection) Side Effects Center for a complete guide to possible side effects


Both the magnitude and duration of central nervous system and cardiovascular effects may be enhanced when ALFENTA (alfenta (alfenta (alfentanil) nil) nil) is administered in combination with other CNS depressants such as barbiturates, tranquilizers, opioids, or inhalation general anesthetics. Postoperative respiratory depression may be enhanced or prolonged by these agents. In such cases of combined treatment, the dose of one or both agents should be reduced. Limited clinical experience indicates that requirements for volatile inhalation anesthetics are reduced by 30 to 50% for the first sixty (60) minutes following ALFENTA (alfenta (alfenta (alfentanil) nil) nil) induction. The concomitant use of erythromycin with ALFENTA (alfentanil) can significantly inhibit ALFENTA (alfenta (alfenta (alfentanil) nil) nil) clearance and may increase the risk of prolonged or delayed respiratory depression.

Cimetidine reduces the clearance of ALFENTA (alfentanil) . Therefore smaller ALFENTA (alfenta (alfenta (alfentanil) nil) nil) doses will be required with prolonged administration and the duration of action of ALFENTA (alfenta (alfenta (alfentanil) nil) nil) may be extended.

Perioperative administration of drugs affecting hepatic blood flow or enzyme function may reduce plasma clearance and prolong recovery.

Read the Alfenta Drug Interactions Center for a complete guide to possible interactions

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

Last reviewed on RxList: 8/14/2008

Side Effects

Additional Alfenta Information

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