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Old doc, new drugs: Tapentadol versus tramadol


Casey Parker


29/08/2018 11:16:13 AM

Dr Casey Parker examines which is best to prescribe.

News teaser
Tapentadol versus tramadol: Which is better to prescribe?

If you’re like me (as a rural GP), you probably started noticing a trickle – and then a flood – of patients being discharged from big city hospitals on this new drug tapentadol.
 
Now, I am a simple rural doctor. When I saw the name tapentadol, I immediately assumed that it was a new version of tramadol, but with more letters to confuse the chaps over at the patent office.
 
I was sort of correct. These drugs are very similar, so it’s worth comparing them.
 
Tramadol
Tramadol is possibly one of the most maligned medications in a GP’s toolbox.
 
It’s an opioid used for pain management. But it’s unpredictable, with a lot of side effects, and often just doesn’t provide much relief. It’s an older drug, dating back to 1977.
 
Tramadol is a prodrug. That means, on its own it doesn’t do much of anything. It gets metabolised in the liver by the cytochrome p450 enzymes into a few active chemicals.
 
But here is the problem – the actual amounts of each of the active metabolites is a bit of a genetic lottery. Depending on the makeup of your cytochromes, you may get:

  • a bunch of destramadol (aka M1), which has a strong mu-opioid receptor affinity and acts like morphine
  • some venlafaxine, which is a serotonin/noradrenaline reuptake inhibitor (SNRI)
  • a mixture of both of the above
  • a whole bunch of other receptors, such as N and M acetylcholine, direct serotonin agonists, and the list goes on.
To some extent, you can ask a patient what effects they felt if they had a dose of tramadol previously.
 
In my experience, you get pretty clear likes or aversion to tramadol. The most common reply is along the lines of, ‘Oh, the drug that made me spew’.
 
Then then there is the risk of serotonin syndrome and seizures. This may come about for a few reasons:
  • Older patients or people with renal/liver disease don’t clear metabolites and they build up
  • Combining it with other serotonin norad-active drugs like antidepressants leads to a double whammy
  • Patients with little metabolism to M1 take more and more doses to achieve analgesia and end up with a bunch of the SNRI metabolites in their systems
All in all, a tricky drug to use, since different patients may have a totally different experience with the drug.
 
Tapentadol
Now let’s introduce tapentadol, first released in 2008. It’s the new and improved version of tramadol, which is arguably not hard to do.
 
So, how is the new kid on the block different?
 
Tapentadol is not a prodrug – it does not rely on metabolism to get it working. So it is what it says on the box – an opioid analgesic. In addition:
  • it has a strong mu-opioid receptor agonist effect, similar to oxycodone
  • it has noradrenaline reuptake inhibitory effects, but not much effect on serotonin reuptake, which makes it a little cleaner
  • there are no active metabolites yet known – so that sounds cleaner, too.
That all sounds nice and neat. A cleaner, direct-acting opioid with fewer side effects. But there must be a catch, right? There always is.
 
The biggest issue is that there is just not enough data available about the safety or efficacy of tapentadol. In the trials used to get it registered, the drug was only just better than a placebo for chronic pain. We need to see some real-world safety data and clinical outcome studies to say exactly how much benefit this drug has.
 
As with any potent opioid, tapentadol is to be used with caution in patients with respiratory failure, other sedatives or noradrenergic agents. It needs to be avoided for at least two weeks after ceasing monoamine oxidase inhibitors (MAOIs) such as moclobemide (though this is rarely used in Australia).
 
Tapentadol side effects are predictable: constipation, nausea and vomiting with some dizziness in up to a third of patients.
 
The risk of developing tolerance and potential for abuse or diversion is likely to be similar to other opiates once the word gets out. This is definitely one to watch carefully when prescribing.
 
In summary
Tapentadol is probably better than tramadol. Which is akin to stating it is funnier than the MIMS – it’s a low bar. It has a more predictable pharmacology, but the evidence is not yet in. We just don’t know the full risk/benefits in 2018.
 
And don’t be fooled by the ‘less abuse potential’ argument; it is a new drug and the same statement was made about oxycodone many moons ago.
 
Watch this space.
 
This article is adapted from Dr Casey Parker’s blog, Broome Docs.



drug mechanisms Tapentadol tramadol



NEVILLE LUDBEY   31/08/2018 10:33:13 AM

GREAT ARTICLE - WISH ALL PHARMACOLOGICAL EXPLANATIONS WERE AS EASY TO FOLLOW.


Nadette   31/08/2018 1:13:40 PM

Thanks Casey, a great read, not often I get a laugh out of analgesic education!


Neel   31/08/2018 2:10:03 PM

Nice article Casey. Very easy to read.


Maria   31/08/2018 3:27:10 PM

Wow, you made that make sense .. answered a lot of questions! Thank you


Jana   2/09/2018 11:15:15 AM

Thanks Casey, good information !


Andrew Lane   4/09/2018 11:11:22 PM

Nicely done. Thanks.


Natalia   5/10/2018 12:48:22 PM

Great article! Look forward to seeing more from you in NewsGP.


Kamlesh meghwal   22/10/2018 11:16:04 PM

Thenkou


Cliff   24/10/2018 5:14:01 PM

Have been on Tapentadol 200mg slow release for chronic knee pain and arthritic pain for approx 6 months. I tend to have addictive traits. Smoker until 6 yrs ago. Drinker
Moderate most days yet i can not say the Tapentadol has any addictive draw to me. Even now i can stop taking it for a few days without withdrawls except return of increased pain. Anyway better than the highly addictive Oxy meds.


Charlotte   8/11/2018 2:45:34 AM

Wow, this was an interesting read! I'm currently on Tramadol, and I've been for nearly 2 years for chronic pain with 2 herniated discs in my neck (C4/C5, C5/C6), impingement syndrome in my left shoulder and so forth. I see now that I am in the latter category, the one that builds up tolerance. And that's a shame, because I'm terrified of drugs like these, but my pain was overwhelming. When I started taking it, I could do with 1-2 a day, and I had days where I didn't take any- mainly because I was too scared, not because the pain had lessened. Now my dose is anywhere from 3-5 in 24 hours, where 5 is a really bad day. I never take 2 at once, being a scaredy cat, and I monitor very intently when I took the pill. I was considering talking to my doctor about going cold turkey, but honestly I'm afraid of the pain becoming worse - and then have no form of lessening it. Should I try this other one, or just quit it all and see how it goes? Been with chronic pain for nearly 5 years now, and I'm 25 years. I'm tired of being in pain and tired of being tired.. Thank you for this post! Very informative, and a fun read.


Stevie   9/11/2018 8:28:10 PM

Is there any ssri or ssni in this drug like tremSR ?


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