Suboxone

 

Suboxone is the more widely used of the two formulations of buprenorphine available to opiate pharmacotherapy consumers in Victoria. Subutex is the other.  Buprenorphine is increasingly popular as an alternative to methadone.

Suboxone contains a 4:1 ratio of buprenorphine/naloxone . Naloxone, an opiate antagonist, reverses the effects of opiates. Under the brand name Narcan, it is used intravenously to assist overdose victims, and is only present in Suboxone as a deterrent to injection (see below). When Suboxone is taken sub-lingually (beneath the tongue), the naloxone has no pharmacological effect.

Only 1-4% of the naloxone is absorbed by the system, and after an hour this small amount has left the system.

 

Film & Tablets:

Suboxone is available in in 2mg and 8mg strengths, coming in two forms: a sub-lingual tablet and, more recently, a sub-lingual film (similar to a Listerine strip). Both are placed beneath the tongue, where they are absorbed directly into the blood-stream through the mucous membrane. (In the case of the film, the inside of the cheek may also be used.)

The effects of the tablets and the film are effectively identical, though trials of film showed a slightly higher bioavailability (i.e. just a little more reaches the system.)

NB: The tablet form of Suboxone will not be available in Victoria after 31 Aug 2013.

 

Basic Pharmacology of Buprenorphine

Buprenorphine is a partial opioid agonist. It binds strongly to the same receptors as other opiates, but stimulates them only weakly, producing very little of an opiate effect.

Once the buprenorphine molecule is locked onto the receptor, it remains there much longer than other opiates like heroin and methadone. If such drugs are taken while on buprenorphine, their effects will be much reduced.

Buprenorphine’s affinity for the receptor is powerful enough to displace opiates like heroin and methadone. For this reason, the initial dose of buprenorphine should be low (i.e. < 8mg) and, ideally, the client should be in the first stages of opioid withdrawal. If a dependent client takes a large dose of buprenorphine after recent use of heroin – or before the onset of withdrawal – the buprenorphine can precipitate immediate and full withdrawal. This is an extremely unpleasant, uncomfortable experience to be avoided at all cost.

 

The Ceiling Effect

An interesting feature of buprenorphine is its ceiling effect.

Up to a certain point, the more buprenorphine that is taken, the greater the opiate effect. Past that point, increasing the dose only results in a longer duration of action and no increased opiate effect. This means that some people can have their daily dose increased (usually doubled) and the dose will last for two days instead of one. This can be very useful for those who have difficulty reaching their dosing points, and can remove the need for take aways during the first month of treatment.

NB: Suboxone take aways are not available in these two day doses, i.e. if you are on 8mg, and receive 16mg to take away, it counts as two take-aways, not one.

Though scientific evidence is scant, this ceiling effect presumably varies with the individual. The maximum allowable dose of buprenorphine is 32mg.

If Suboxone is taken as recommended, the naloxone should have no effect. Any small amount that is absorbed will leave the body within one hour of dosing.

 

Injecting Suboxone

If Suboxone is injected, the naloxone and buprenorphine will compete to occupy the receptors, causing an uncomfortable delay before any effects are felt. The buprenorphine will eventually displace the naloxone, but up to twenty minutes may pass before this occurs.

If another opiate, like heroin or oxycodone, is present in the system when injecting Suboxone, precipitated withdrawal will result, as the opiate will be rapidly displaced by both the buprenorphine and naloxone.

Injecting Suboxone carries serious health risks and is not recommended. If the medication is removed from the mouth prior to injection, these risks are compounded. For more information about the harms associated with injecting Suboxone, please contact PAMS.

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Take Away Doses of Buprenorphine-Naloxone (Suboxone)

The number of take away doses available for those taking Suboxone depends on their stability and how long they have been on the program.

For the first two weeks of treatment, clients must attend each day for their dose. After this, if the client is considered stable, some take-away doses may be prescribed, see below for further details:

• After two weeks of continuous treatment and considered stable (on the correct dose and not missing doses)  – eligible for up to 2 take away doses per week

• After two months of continuous treatment and considered stable (on the correct dose and not missing doses)  – eligible for up to 5 take away doses per week

• After six months of continuous treatment and considered stable (on the correct dose and not missing doses)  – eligible for up to 6 take away doses per week

 

Minimal Supervision Regime

The Minimal Supervision Regime or MSR is an additional category of of take away doses available to people who have been receiving Suboxone for a considerable period of time, and who have been assessed as very stable by their doctor. Under the MSR consumers may receive up to a 28 day supply of Suboxone at any one time. This type of supply can be dispensed like any other medication in a single, labelled container.

To access the MSR a client must arrange to have their GP consult with an Addiction Medicine Specialist (AMS). If satisfied that the client is stable, the specialist will then sign off on a separate, dedicated permit. It may also be neccessary for the client to have a one-off consultation with the AMS.