Weekly Dose: fentanyl, the anaesthetic that may have been used as a chemical weapon on Chechen rebels

Fentanyl is a synthetic analgesic (pain relieving) drug in the same class as morphine. It is used to treat acute or chronic pain, including for epidurals given to women during childbirth.

It is thought that in 2002 fentanyl, or a drug based on it, was used by Russian special forces to disable Chechen rebels after a four-day siege in the Dubrovka theatre in Moscow.

Use

Fentanyl was developed in the 1950s by the Belgian doctor Paul Janssen who went on to establish Janssen Pharmaceuticals, which later merged into the global pharmaceutical giant Johnson & Johnson.

The drug is used to treat acute or chronic pain, and acts by binding to opioid receptors throughout the body, thereby inhibiting the transmission of pain signals to the brain.

It is thus an opioid-based drug, in the same class as codeine, methadone, oxycodone, pethidine, and tramadol. It is considered to be up to 100 times more potent than morphine in its ability to relieve pain.

The drug Naloxone can be used to reverse the effects of fentanyl in overdose cases.

Formulations

Women who are given an epidural during childbirth will be given an injection that contains a combination of fentanyl and one of two other painkillers, bupivacaine or ropivacaine, both of which are derived from cocaine. The injection is given into the space around the spinal cord, and as such can only be administered by a trained anaesthetist.

For those suffering long-term pain, fentanyl is also supplied in several different formulations. These include lozenges, which are designed to be sucked like lollies, sublingual tablets, which dissolve quickly under the tongue, and patches that are placed on the skin.

For children aged between 1 and 12 years, fentanyl may also be administered as a nasal spray.

Side effects

The most common side effects include a rash, redness of the skin, itchiness, and an increased heart rate. While patients may experience the same nausea, vomiting, and constipation that are common of all opioid-based drugs, these side effects are usually less severe for fentanyl.

Fentanyl can also have a depressive effect on coughing and is known to depress the breathing of some patients.

Possible use on Chechen rebels

In October 2002 a group of Chechen rebels took hundreds of people hostage at the Dubrovka theatre in Moscow during a sold-out performance of the musical Nord Ost.

Having made no progress for nearly four days, Russian special forces pumped a powerful “sleeping gas” into the building, rendering all the rebels and theatre patrons unconscious.

Because the military did not give any prior warning of what they were going to do it was more than an hour before ambulances were available to take people to hospital. In addition, the military refused to provide the name of the gas they had used to medical staff, making treatment decisions very difficult.

It is widely believed the gas used was either fentanyl, or some other fentanyl-based drug, because some patients were found to have the sleeping effects reversed when they were administered naloxone.

Combined, more than 100 of the rebels and theatre patrons died from the gassing.

Cost

Fentanyl is only available by prescription because it is classified as a Schedule 8 medicine - drug of addiction. The cost of the lozenges, tablets, and patches is subsidised by the Australian pharmaceutical benefits scheme and are supplied to patients at a maximum cost of A$38.30 per packet; although the number of doses provided in each packet can vary based on the formulation.

Public hospital patients given fentanyl as an epidural during child birth will not be charged for the cost of the drug. Private patients will have the cost of the drug included as part of their treatment bill which is usually covered by their health insurance.

Dr Wheate in the past has received funding from the ACT Cancer Council, Tenovus Scotland, Medical Research Scotland, Scottish Crucible, and the Scottish Universities Life Sciences Alliance. He is affiliated with the Royal Australian Chemical Institute.