For the induction of Bup, COWS must be 9,
Even higher helps you soon to feel fine.
With Methadone, the breathing center is key -
Dose is gradually raised on your way to be free.

Most clinics that offer MOUD ask patients to plan a significant block of time on their first day at the clinic.  A complete medical history, physical exam, and counseling assessment are accomplished the first day.  The admitting medical staff will assist the patient in the decision of which medication they would like to try.  If Buprenorphine is the chosen medication, the patient will be rated by the Clinical Opioid Withdrawal Scale (COWS).  As mentioned at the end of the previous chapter, induction with Buprenorphine can be challenging.  A score of 9 on the COWS is a minimum number as a lower score increases the risk of ‘precipitated withdrawal’.  The very property that makes Buprenorphine safer in overdose situations can cause severe withdrawal symptoms if the patient is not in full withdrawal when the first dose is administered.  For this reason, the patient should not have taken any opioids for 24-48 hours before starting Buprenorphine.  For a patient taking Methadone or long-acting preparations of other opioids, 48-96 hours of abstinence are required.  The medical staff measures heart rate, respiration rate, blood pressure, pupil size, pilo-erection (goose bumps), along with other more subjective symptoms of opioid withdrawal to arrive at a COWS score.  Patients with scores at 9 or higher should expect to feel significantly better during the induction process.  In general, the higher the COWS score (those having worse withdrawal), the more immediate and dramatic the benefit when Buprenorphine is administered.

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In recent years, many patients know this to be true.  Sadly, some have learned this to be true the hard way.  They took someone else’s Buprenorphine thinking it would be a good substitute when they were unable to get their usual Heroin or other opioid, only to take it too early before withdrawal was in full effect, and have had a terrible experience.  I have had many patients tell me it is one of the worst experiences they have ever had. Methadone also has its challenges in induction, though not the problem of precipitated withdrawal.  Each opioid develops its own tolerance to the breathing and heart rate centers.  Tolerance is the gradual adjustment that the opioid receptors develop when exposed repeatedly to the patient’s opioid of choice.  Tolerance is the reason that higher doses are required over time to achieve the same degree of ‘high’ or euphoria.  Though many effects of opioids are ‘cross-tolerant’, the effect on the breathing center is not.  

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To make this easier to understand, let’s use the following example.  We all know 100 pennies = 20 nickels = 10 dimes = 4 quarters = 1 dollar.  If you go to the store to buy an item for 1 dollar, 4 quarters will work as well as a dollar bill.  Many persons who are addicted to opioids know how many Norcos they might need if they cannot obtain their usual dose of Heroin.  If they have used Methadone recently, they may also know how much they need.  But, if they have never used Methadone, they might stop breathing even on lower doses. The breathing center that has never been exposed to Methadone is almost like the breathing center of a person who has never taken any opioids.  The other opioids taken have not created cross-tolerance to Methadone at the breathing center.  Continuing the above analogy, it is almost the same situation as a person coming from Mexico who knows that 20 pesos is the same as 1 dollar but is harassed by the store owner when he tries to use the 20 pesos to buy the dollar object.  Methadone at what is thought to be an equivalent dosage can shut down the breathing center in the person who has never taken it. For that reason, we must start at lower dosages when a person has not ever or recently taken Methadone.

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We rely on the long-acting effects of Methadone during induction to mute or make the withdrawal symptoms tolerable as we work up the dose to the ‘normalizing dose’. Micro-dosing is a term that has been applied when transitioning from Methadone to Buprenorphine.  If a patient is on Buprenorphine and wants to transition to Methadone, the medical staff simply starts a taper of Buprenorphine and a gradual increase of Methadone until the normalizing dose of Methadone and tapering off Buprenorphine is achieved. Changing from Methadone to Buprenorphine is more challenging.  Earlier in this chapter, reference was made to the need of being in withdrawal with a COWS score of 9 or above to safely start Buprenorphine.  If Methadone is the opioid a patient is taking, a longer period of abstinence is required.  These are guidelines for new patients.

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When a patient is on the program on Methadone and desires a trial of Buprenorphine, we can institute a procedure termed ‘Micro-dosing’.  The fact that Buprenorphine has the highest affinity to the Mu receptor allows this procedure.  The patient does not have to taper off Methadone or go through 48-72 hours of abstinence. Methadone is continued on the ‘normalizing’ dose.  Buprenorphine is started at a very low dose to not precipitate withdrawal.  The dose is very gradually increased while Methadone is continued on the regular dose.  Buprenorphine gently replaces Methadone from the Mu receptor, not causing withdrawal.  When Buprenorphine is close to the anticipated ‘normalizing dose’, Methadone is stopped.  Since it has gradually been blocked from attaching to the Mu receptor, no withdrawal symptoms are experienced. If withdrawal symptoms are experienced on the day Methadone is stopped, the Buprenorphine dose can be increased and will usually treat the withdrawal symptoms.  It is possible that more aggressive Buprenorphine dosing may be required for several days after the Methadone is stopped, but most often that will not be the case.  

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