6 ADVERSE REACTIONS
The following serious adverse reactions are described, or described in greater detail, in other sections:
- Addiction, Abuse, and Misuse [see Warnings and Precautions (5.1)]
- Life-Threatening Respiratory Depression [see Warnings and Precautions (5.2)]
- Muscle Rigidity and Skeletal Muscle Movement [see Warnings and Precautions (5.4)]
- Interactions with Benzodiazepines and CNS Depressants [see Warnings and Precautions (5.5)]
- Serotonin Syndrome [see Warnings and Precautions (5.7)]
- Bradycardia [see Warnings and Precautions (5.8)]
- Gastrointestinal Adverse Reactions [see Warnings and Precautions (5.11)]
- Seizures [see Warnings and Precautions (5.12)]
6.1 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 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 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 movements1
Respiratory: Apnea1, postoperative respiratory depression
Central Nervous System: Blurred vision, dizziness1, sleepiness/postoperative sedation
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
Injection Site: Pain2
Musculoskeletal: Skeletal muscle rigidity of neck and extremities
6.2 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.
Androgen deficiency: Cases of androgen deficiency have occurred with chronic use of opioids [see Clinical Pharmacology (12.2)].
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.