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Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

Adverse Events In Clinical Trials

The safety of SUBUTEX sublingual tablet was supported by clinical trials using SUBUTEX sublingual tablet, SUBOXONE (buprenorphine/naloxone sublingual tablet) and other trials using buprenorphine sublingual solutions. In total, safety data were available from 3214 opioid-dependent subjects exposed to buprenorphine at doses in the range used in treatment of opioid addiction.

Few differences in adverse event profile were noted between SUBUTEX or buprenorphine administered as a sublingual solution.

The following adverse events were reported to occur by at least 5% of patients in a 4-week study (Table 1).

Table 1: Adverse Events ≥ 5% by Body System and Treatment Group in a 4-week study

Body System / Adverse Event (COSTART Terminology) N (%) N (%)
SUBUTEX 16 mg/day
N=103
Placebo
N=107
Body as a Whole
Asthenia 5 (4.9%) 7 (6.5%)
Chills 8 (7.8%) 8 (7.5%)
Headache 30 (29.1%) 24 (22.4%)
Infection 12 (11.7%) 7 (6.5%)
Pain 19 (18.4%) 20 (18.7%)
Pain Abdomen 12 (11.7%) 7 (6.5%)
Pain Back 8 (7.8%) 12 (11.2%)
Withdrawal Syndrome 19 (18.4%) 40 (37.4%)
Cardiovascular System
Vasodilation 4 (3.9%) 7 (6.5%)
Digestive System
Constipation 8 (7.8%) 3 (2.8%)
Diarrhea 5 (4.9%) 16 (15.0%)
Nausea 14 (13.6%) 12 (11.2%)
Vomiting 8 (7.8%) 5 (4.7%)
Nervous System
Insomnia 22 (21.4%) 17 (15.9%)
Respiratory System
Rhinitis 10 (9.7%) 14 (13.1%)
Skin And Appendages
Sweating 13 (12.6%) 11 (10.3%)

The adverse event profile of buprenorphine was also characterized in the dose-controlled study of buprenorphine solution, over a range of doses in four months of treatment. Table 2 shows adverse events reported by at least 5% of subjects in any dose group in the dose-controlled study.

Table 2: Adverse Events ( ≥ 5%) by Body System and Treatment Group in a 16-week Study

Body System /Adverse Event (COSTART Terminology) Buprenorphine Dose*
Very Low*
(N=184) N (%)
Low*
(N=180) N (%)
Moderate*
(N=186) N (%)
High*
(N=181) N (%)
Total*
(N=731) N (%)
*Sublingual solution. Doses in this table cannot necessarily be delivered in tablet form, but forcomparison purposes:
“Very low” dose (1 mg solution) would be less than a tablet dose of 2 mg
“Low” dose (4 mg solution) approximates a 6 mg tablet dose
“Moderate” dose (8 mg solution) approximates a 12 mg tablet dose
“High” dose (16 mg solution) approximates a 24 mg tablet dose
Body as a Whole
Abscess 9 (5%) 2(1%) 3 (2%) 2(1%) 16(2%)
Asthenia 26 (14%) 28 (16%) 26 (14%) 24 (13%) 104 (14%)
Chills 11 (6%) 12 (7%) 9 (5%) 10 (6%) 42 (6%)
Fever 7 (4%) 2 (1%) 2 (1%) 10 (6%) 21 (3%)
Flu Syndrome 4 (2%) 13 (7%) 19 (10%) 8 (4%) 44 (6%)
Headache 51 (28%) 62 (34%) 54 (29%) 53 (29%) 220 (30%)
Infection 32 (17%) 39 (22%) 38 (20%) 40 (22%) 149 (20%)
Injury Accidental 5 (3%) 10 (6%) 5 (3%) 5 (3%) 25 (3%)
Pain 47 (26%) 37 (21%) 49 (26%) 44 (24%) 177 (24%)
Pain Back 18 (10%) 29 (16%) 28 (15%) 27 (15%) 102 (14%)
Withdrawal Syndrome 45 (24%) 40 (22%) 41 (22%) 36 (20%) 162 (22%)
Digestive System
Constipation 10 (5%) 23 (13%) 23 (12%) 26 (14%) 82 (11%)
Diarrhea 19 (10%) 8 (4%) 9 (5%) 4 (2%) 40 (5%)
Dyspepsia 6 (3%) 10 (6%) 4 (2%) 4 (2%) 24 (3%)
Nausea 12 (7%) 22 (12%) 23 (12%) 18 (10%) 75 (10%)
Vomiting 8 (4%) 6 (3%) 10(5%) 14 (8%) 38 (5%)
Nervous System
Anxiety 22 (12%) 24 (13%) 20 (11%) 25 (14%) 91 (12%)
Depression 24 (13%) 16 (9%) 25 (13%) 18 (10%) 83 (11%)
Dizziness 4 (2%) 9 (5%) 7 (4%) 11 (6%) 31 (4%)
Insomnia 42 (23%) 50 (28%) 43 (23%) 51 (28%) 186(25%)
Nervousness 12 (7%) 11 (6%) 10(5%) 13 (7%) 46 (6%)
Somnolence 5 (3%) 13 (7%) 9 (5%) 11 (6%) 38 (5%)
Respiratory System
Cough Increase 5 (3%) 11 (6%) 6 (3%) 4 (2%) 26 (4%)
Pharyngitis 6 (3%) 7 (4%) 6 (3%) 9 (5%) 28 (4%)
Rhinitis 27 (15%) 16 (9%) 15 (8%) 21 (12%) 79 (11%)
Skin And Appendages
Sweat 23 (13%) 21 (12%) 20 (11%) 23 (13%) 87 (12%)
Special Senses
Runny Eyes 13 (7%) 9 (5%) 6 (3%) 6 (3%) 34 (5%)
*Sublingual solution. Doses in this table cannot necessarily be delivered in tablet form, but for comparison purposes:
“Very low” dose (1 mg solution) would be less than a tablet dose of 2 mg
“Low“ dose (4 mg solution) approximates a 6 mg tablet dose
“Moderate” dose (8 mg solution) approximates a 12 mg tablet dose
“High” dose (16 mg solution) approximates a 24 mg tablet dose

Adverse Events - Post-marketing Experience With SUBUTEX Sublingual Tablets

The most frequently reported post-marketing adverse events with SUBUTEX not observed in clinical trials, excluding drug exposure during pregnancy, was drug misuse or abuse.