I also found this reference if you're interested. I put in a section of it that tells of a guy who was abusing heroin and then decided he wanted to get clean again, and he took 40 mg buprenorphine and had severe withdrawal for 3-4 days.
"We report a patient enrolled in buprenorphine maintenance treatment. At enrolment he was 35 years old, with a 10-year history of heroin use, poorly controlled asthma, and features of depression and anxiety. He started taking buprenorphine at a dose of 8 mg per day, increasing to a maintenance dose of 24 mg daily within three weeks. Consecutive weekly urine samples over six months indicated no heroin use.
After 12 months of continuous therapy, his buprenorphine dose had reduced to 16 mg every second day, and was continuing to be gradually reduced. At this time the patient's long-term relationship ended, he started drinking alcohol heavily and recommenced heroin use. Unbeknown to pharmacy staff at the time, he was not routinely taking his buprenorphine as directed; instead, after dosing he would leave the pharmacy quickly, spitting out the tablets before they had dissolved. In this way he saved 11 tablets (8 mg each).
After several weeks of regular heroin use without taking buprenorphine (although still attending the pharmacy and continuing to accumulate buprenorphine), he decided to re-initiate treatment of his own accord with the accumulated buprenorphine tablets. He took 40 mg buprenorphine at once, which precipitated uncomfortable opiate withdrawal symptoms (agitation, nausea, sweating, abdominal cramps) within an hour of ingestion. In an attempt to relieve the withdrawal discomfort, he then took a further 24 mg, but this provided no relief. He took a further 16 or 24 mg, but continued to experience persistent agitation, poor sleep, abdominal cramps, diarrhoea and sweating.
The patient presented to the clinic two days later. He appeared restless and agitated and was requesting more buprenorphine. He was dispensed 16 mg buprenorphine, but continued to experience symptoms of opiate withdrawal overnight, despite using heroin. The next morning, still appearing agitated, tense and distressed, he told treatment staff what had happened. He was subsequently transferred to methadone therapy, with resolution of his withdrawal discomfort.
Discussion
This case highlights a number of features of buprenorphine's unique pharmacology which are pertinent to healthcare providers. Firstly, it shows the relative safety of buprenorphine in very high doses. This patient took 88 mg of buprenorphine within one day — almost three times the maximum recommended daily dose (32 mg). This is consistent with another reported case of massive buprenorphine overdose, in which 112 mg was taken orally, also without significant respiratory depression.2 This safety is due to the ceiling effects of buprenorphine in high doses.
Secondly, rather than experiencing features of opiate overdose (eg, respiratory depression, sedation), our patient experienced precipitated opiate withdrawal. When buprenorphine is taken soon after opiates with less opiate-receptor affinity, such as heroin and methadone, it displaces them from the receptors. Since buprenorphine is only a partial agonist, this causes a drop in the level of overall opiate activity and is experienced as opiate withdrawal. While we are aware of only three other reported cases of buprenorphine-precipitated withdrawal after heroin use,3,4 it is common in methadone patients transferring to buprenorphine therapy, particularly with higher doses of methadone (> 40 mg), a short time between the last methadone dose and the first buprenorphine dose and when higher initial buprenorphine doses are used.5-8 Withdrawal symptoms typically commence within 1–3 hours of the first buprenorphine dose and can last for several days."
Med J Aust. 2002 Feb 18;176(4):166-7.
Severe opiate withdrawal in a heroin user precipitated by a massive buprenorphine dose.
Clark NC, Lintzeris N, Muhleisen PJ.