Tuesday, 10 May 2011

Opiates in Pregnancy - Subutex, Suboxone or Methadone?

You don't need a lecture. You want the facts.

What you will find here is the highly sought after and difficult to find, up to date facts about the use of Subutex, Suboxone or Methadone during pregnancy. I have written this for mother's (and their families)who are already on one of the three when they discover they are pregnant.

Regardless of how you found yourself in this situation, you have some concerns. I urge you to read this information slowly and bookmark this page for future reference. I have put a lot of time and research into making sure that this info is correct, has studies or reports to support it and is up to date. Please follow the links for additional reading.

Methadone - Subutex - Suboxone - How Do They Work

Before we can assess what effects these medications will have on your baby, you need to understand how they work on you. There are three ways to treat opiate dependency:

Agonists - all opiates are agonists (including Methadone). They work by stimulating the receptors in your brain.

Antagonists - (is. Naloxone, Naltrexone) work by coating the receptors and repelling the opiates that may encounter them.

Partial Agonists - (Buprenorphine = Subutex or Suboxone) work by coating the receptors whilst allowing a little stimulation at the same time.

Confused? Let me simplify...
Agonists = the door is wide open
Antagonists = the door is locked
Partial Agonists = the door is left ajar

Withdrawing during pregnancy is very risky business and should be avoided wherever possible. Therefore antagonists are out of the question. Your prescribing Doctor will recommend that you keep the levels in your bloodstream as steady as possible to avoid the risks of miscarriage or premature labour.

Methadone works like any other opiate by stimulating the receptors. Subutex and Suboxone both contain the same active ingredient - Buprenorphine. Suboxone can be considered Subutex plus. It contains Buprenorphine and an extra ingredient - Naloxone - to prevent it's misuse. The withdrawals are milder (though still very real) and usually shorter.

Which One Is Right For Me?

If you are on Suboxone, you should change to Subutex. Many countries that are in an effort to phase this drug out make an exception for pregnant and lactating mothers. Naloxone (the extra ingredient found in Suboxone) has been observed to cause seizures in the severe withdrawals - a most undesired effect in neonates.

Subutex is now the favoured choice over methadone - You can read the Methadone vs Subutex study here (once you've finished reading this of course!). 

The downside of Buprenorphine is that (since it is unethical to preform studies on unborn babies) there is very little knowledge about it's long term effects on the foetus. Whilst most Doctors won't hesitate to recommend this as the first or even only choice for dependent mothers, many women are put off by the uncertainty.

Methadone, on the other hand, has been treating addicts for over 40 years. There has been thousands of successful pregnancies and there has been dozens as studies into the long term effects Methadone had/has on those babies who are now adults. 

If that is the case - if we know the risks and effects of methadone during pregnancy - why is Subutex a Doctors first choice? Great question - which I'll answer as soon as I tell you what NAS is.

Neonatal Abstinence Syndrome (or NAS for short) was once referred to as Neonatal Withdrawal Syndrome.
It occurs in up to 90% of the babies born to opioid dependent mothers and come with a whole host of complications. 

You can learn more about what NAS is and caring for your baby here.

I also wrote a companion article (much like this one) called NAS: Subutex Suboxone in Pregnancy that you can check out here.  

And while you are opening up all of these extra windows (right click or hold Ctrl + W) you may as well check out this printable brochure made by one of Australia's leading Maternal Health hospital's about NAS.

The Statistics of Using Subutex in Pregnancy

  • 55-94% of babies born to opioid dependent mothers will exhibit symptoms of NAS.
  • There have only been 21 published reports of the use of Buprenorphine (Subutex and Suboxone) in pregnancy.
  • These reports involved the study of 309 infants who had been exposed to Buprenorphine in utero.
  • Of these 309 babies, 62% exhibited NAS
  • Of these 309 babies, 48% exhibited NAS and required treatment (though nearly half of this group was also exposed to illicit drugs too).
  • Buprenorphine babies begin to present with symptoms of NAS within 12-48hrs of birth
  • Withdrawals peak at approx 72-96 hrs.
To put it simply:
Opiates = 96% likelihood of NAS
Subutex = 62% likelihood of NAS
And only 48% of Subutex need medical intervention (which involves treating baby with tiny amounts of morphine) so that's a huge 52% of babies who have been exposed to Subutex in utero that need significant treatment.  
This is the reason that doctors favour Subutex over methadone - the withdrawals are milder, shorter and require less medical intervention. (You can read that report here)
To make sure your baby falls in that group, use your Subutex correctly as your Doctor has prescribed and avoid all other drugs - the odds will be stacked in your favour.
Please visit this address to print (or at least read) your own copy of the Finnegan Scoring Sheet - this is the system used to measure your babies withdrawals and it would be wise to be familiar with it...just in case =)

Will My Baby Be Brain Damaged
This unfortunately is one that is impossible to answer. Because Subutex is relatively new on the market, there just isn't enough evidence to give us any realistic figures. The largest most notable concerns with Subutex and Methadone are fetal growth issues and pre-term (or premature) issues. 
Whilst many will attest to these children struggling at school or having behavioural difficulties, it is hard to determine whether it caused by exposure in the womb or caused by family issues - is it nature or nurture?

Subutex and Breastfeeding
Is a whole new kettle of fish which I have addressed in another post. I suggest that you take a moment to read up and make an informed decision about the best choice for you. The very short answer Many Doctors are now giving it their unofficial approval.   

No comments:

Post a Comment