Buvidal is presented as a prefilled syringe containing 8mg, 16mg, 24mg, 32mg, 64mg, 96mg or 128mg buprenorphine as a prolonged-release solution for injection.
Weekly or monthly dosing
Patients who have not previously been exposed to buprenorphine should be given a 4mg sublingual dose of the drug and observed for an hour before the first administration of Buvidal. If buprenorphine tolerability is confirmed, patients should then be started on Buvidal 16mg by subcutaneous injection with one or two additional 8mg doses given at least one day apart, to reach a target dose of 24mg to 32mg during the first week.
The recommended dose for the second week is the total dose administered during the initiation week. Monthly treatment may be started once patients are stabilised on weekly treatment (four weeks or more, where practical). Patients switching from sublingual buprenorphine can start directly on the weekly or monthly schedule.
The dose should be adjusted according to response, to a maximum weekly dose of 32mg plus an additional 8mg dose or a maximum monthly dose of 128mg plus an additional 8mg dose.
In patients taking methadone, the methadone dose should be reduced to a maximum of 30mg daily and an interval of at least 24 hours allowed between the last dose and initiation of Buvidal therapy. In patients using heroin or short-acting opioids an interval of at least 6 hours after the last dose should be allowed before initiating Buvidal therapy.
The safety and efficacy of Buvidal were assessed in a double-blind, double-dummy, active-controlled, flexible dose study in 428 patients with moderate to severe opioid dependence.
Patients in the Buvidal group (n=213) received weekly injections (16mg to 32mg) during the first 12 weeks followed by monthly injections (64mg to 160mg) during the last 12 weeks, plus daily doses of sublingual placebo tablets for the whole 24 weeks.
Patients in the sublingual buprenorphine/naloxone group (n=215) received weekly placebo injections for 12 weeks followed by monthly placebo injections for 12 weeks, plus daily sublingual buprenorphine/naloxone tablets for the whole 24 weeks (8mg to 24mg for the first 12 weeks and 8mg to 32mg for the second 12 weeks).
The study met the primary endpoint of non-inferiority in mean percentage of urine samples negative for illicit opioids during treatment weeks 1 to 24 for the Buvidal group compared with the sublingual buprenorphine/naloxone group.
In a 48-week open-label study involving 190 patients switching from sublingual buprenorphine (with or without naloxone) and 37 patients new to buprenorphine, the percentages of patients with illicit-opioid-negative urine samples increased from 78.8% to 84.0% and from 0% to 63.0%, respectively, from baseline to the end of the study period.