Opioids and the Concern Over Respiratory Depression:
Methadone vs. Suboxone (Buprenorphine)
The ability of opioids to depress or lessen breathing is well known. Alarmists think this is one reason not to treat chronic pain, and this fuels the suffering of tens of millions. The effect of opioids on breathing is very short-lived, and really only applies to patients involved in overdosing, mixing high doses of very sedating medications or massive dose increase in virgin opioid patients—patients who have never taken an opioid and are started on massive doses. Also, patients with COPD or other severe lung disease might be more careful, esp. in the first week of treatment.
Some publications have warned about mixing the anti-anxiety agents, the benzodiazepines, especially in an IV form with buprenorphine. This abstract below makes some important points on this issue. Including the finding that buprenorphine is not more depressing to respirations than methadone in lab animals.
Methadone and buprenorphine are the two main opioid substitution treatments for heroin dependence implicated buprenorphine currently offered in Australia. A number of publications have as being potentially dangerous in combination with benzodiazepines but no comparison has been made to the relative dangers of benzodiazepines combined with buprenorphine or methadone. The effect of i.v. Methadone and buprenorphine on respiration was investigated by evaluating arterial blood pCO(2,) pO(2) and pH, and measuring respiratory rate in rats. Measurements were taken at 0, 15, 30, 60, 120, 180 and 240min after i.v. administration of methadone or buprenorphine. Effects on respiration were greatest 15min after i.v. drug administration. The effect of methadone and buprenorphine on respiration was compared with and without diazepam pretreatment (20mg/kg). Buprenorphine alone exhibited a bell shaped dose response inhibition of respiration; however the plateau of the dose response inhibition on respiration was lost when administered in combination with diazepam. Methadone showed a dose-dependent inhibitory effect on respiration, which was potentiated with diazepam pretreatment. While the effect of diazepam pretreatment was the abolishment of the protective bell shaped dose response effect on respiration, the effect of buprenorphine and diazepam was not greater than methadone and diazepam.
Nielsen S, Taylor DA. The effect of buprenorphine and benzodiazepines on respiration in the rat. Drug Alcohol Depend. 2005 Jul 1;79(1):95-101. Epub 2005 Feb 17.