Alfentanil Overdose

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Alfentanil is a semi-synthetic opioid painkiller that’s used as anesthesia during invasive surgeries. It’s fast-acting, with an onset of one to two minutes. Alfentanil must be administered by a trained anesthesiologist.

The amount of the drug that’s necessary to overdose is highly dependent on several factors, including size and weight, age, liver function, and kidney health.

Alfentanil is an analog of fentanyl and has roughly one-third the duration of action and one-quarter to one-tenth the potency of fentanyl. Alfentanil is more prone to inducing severe respiratory depression, which is the primary concern with regard to fatal overdoses. Alfentanil has significantly lower effects on cardiovascular depression than fentanyl. Alfentanil use and abuse can contribute to developing an opioid dependence and addiction.

Alfentanil Overdose

Patients must be closely monitored for respiratory depression while they are administered alfentanil. The severity of respiratory depression can vary dramatically according to each patient’s unique metabolism of the drug.

Respiratory depression is the primary side effect of Alfentanil use, with severe respiratory depression being the primary sign of overdose.  On rare occasions, respiratory depression can persist after the drug’s typical duration of action is complete. Pinpoint pupils and severely decreased level of consciousness are also primary signs of an opioid overdose.

Common side effects of alfentanil use and abuse can include muscular rigidity, especially of the thoracic muscles (chest), bradycardia (slow heart rate), hypotension (low blood pressure), nausea, vomiting, and apnoea. Less common side effects include laryngospasm and allergic reactions such as bronchospasm, anaphylaxis, and urticaria.

Skeletal muscle rigidity can occur at doses below 20 micrograms/kg. Alfentanil doses above 120 micrograms/kg consistently produce the immediate onset truncal muscle rigidity. Cases of severe muscle rigidity can be reduced by injecting the drug slowly and using benzodiazepines and muscle relaxants prior to alfentanil administration. Combining these drugs with opioids like alfentanil can easily result in a fatal overdose when administered outside of the hospital setting.

Alfentanil Overdose

Alfentanil is manufactured as a sterile solution of alfentanil hydrochloride with 0.5 mg/mL alfentanil and 9.0mg/mL sodium chloride for injection to 1 mL. The effective dosage ranges will vary dramatically depending on the patient’s body-fat percentage, kidney, and liver health.

The patient’s age is also taken into account in elderly patients due to the increased likelihood of suboptimal liver and kidney function. Alfentanil dosage is typically reduced in elderly patients due to reduced clearance. On average, Alfentanil doses for elderly patients are one-third of the typical standard dose given to younger adult patients.

The dosage administered to obese patients is also expected to be lower due to reduced clearance rate. Individuals with liver disease may require significantly reduced doses of alfentanil. Reduced clearance and decreased plasma protein concentrations can lead to prolonged clinical effects. Patients with poor kidney health should be monitored closely, although the complications that arise from renal failure are less impactful due to alfentanil being primarily metabolized by the liver.

In the event of alfentanil overdose, standard opioid overdose protocol should be followed. The primary concerns are supporting patient respiration, ensuring adequate ventilation, and administering naloxone. Naloxone is a powerful opioid antagonist and is the gold standard for rapidly reversing the effects of opioids in the body. When administered intranasally or intravenously, naloxone can completely negate the effects of opioids like alfentanil within seconds. Staff must then work to stabilize the patient’s vitals via assisted breathing and oxygen therapy as needed.

Several medications can increase the risks of complications that lead to overdose. Pharmacokinetic data indicates that alfentanil metabolism may be inhibited by the medications voriconazole, diltiazem, fluconazole, and cimetidine. Other studies suggest that itraconazole, ketoconazole, and ritonavir may inhibit the metabolism of alfentanil and increase the risk of prolonged respiratory depression. Patients should also avoid taking irreversible MAO inhibitors within two weeks of taking alfentanil. Selective serotonin reuptake inhibitors should also be avoided due to the risk of potentially life-threatening serotonin overload.

For more information about opioid overdose, visit The Recovery Village at We can also be contacted 24/7, toll-free at 855-548-9825. Call us today to learn more about the risks associated with substance abuse.

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