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.
A total of 5,415 patients were treated with buprenorphine transdermal system in controlled and open-label chronic pain clinical trials. Nine hundred twenty-four subjects were treated for approximately six months and 183 subjects were treated for approximately one year. The clinical trial population consisted of patients with persistent moderate to severe pain.
The most common serious adverse drug reactions (all <0.1%) occurring during clinical trials with buprenorphine transdermal system were: chest pain, abdominal pain, vomiting, dehydration, and hypertension/blood pressure increased.
The most common adverse events (≥ 2%) leading to discontinuation were: nausea, dizziness, vomiting, headache, and somnolence.
The most common adverse reactions (≥ 5%) reported by patients in clinical trials comparing buprenorphine transdermal system 10 or 20 mcg/hour to placebo are shown in Table 2, and comparing buprenorphine transdermal system 20 mcg/hour to buprenorphine transdermal system 5 mcg/hour are shown in Table 3 below:
Table 2: Adverse Reactions Reported in ≥ 5% of Patients during the Open-Label Titration Period and Double-Blind Treatment Period: Opioid-Naïve Patients | Open-Label
Titration Period
Buprenorphine | Double-Blind Treatment Period |
| Buprenorphine | Placebo |
| MedDRA Preferred Term | (N = 1024) | (N = 256) | (N = 283) |
| Nausea | 23% | 13% | 10% |
| Dizziness | 10% | 4% | 1% |
| Headache | 9% | 5% | 5% |
| Application site pruritus | 8% | 4% | 7% |
| Somnolence | 8% | 2% | 2% |
| Vomiting | 7% | 4% | 1% |
| Constipation | 6% | 4% | 1% |
Table 3: Adverse Reactions Reported in ≥ 5% of Patients during the Open-Label Titration Period and Double-Blind Treatment Period: Opioid-Experienced Patients | Open-Label
Titration Period
Buprenorphine | Double-Blind Treatment Period |
| Buprenorphine 20 | Buprenorphine 5 |
| MedDRA Preferred Term | (N = 1160) | (N = 219) | (N = 221) |
| Nausea | 14% | 11% | 6% |
| Application site pruritus | 9% | 13% | 5% |
| Headache | 9% | 8% | 3% |
| Somnolence | 6% | 4% | 2% |
| Dizziness | 5% | 4% | 2% |
| Constipation | 4% | 6% | 3% |
| Application site erythema | 3% | 10% | 5% |
| Application site rash | 3% | 8% | 6% |
| Application site irritation | 2% | 6% | 2% |
The following table lists adverse reactions that were reported in at least 2.0% of patients in four placebo/active-controlled titration-to-effect trials.
Table 4: Adverse Reactions Reported in Titration-to-Effect Placebo/Active-Controlled Clinical Trials with Incidence ≥ 2%| MedDRA Preferred Term | Buprenorphine
(N = 392)
| Placebo
(N = 261)
|
| Nausea | 21% | 6% |
| Application site pruritus | 15% | 12% |
| Dizziness | 15% | 7% |
| Headache | 14% | 9% |
| Somnolence | 13% | 4% |
| Constipation | 13% | 5% |
| Vomiting | 9% | 1% |
| Application site erythema | 7% | 2% |
| Application site rash | 6% | 6% |
| Dry mouth | 6% | 2% |
| Fatigue | 5% | 1% |
| Hyperhidrosis | 4% | 1% |
| Peripheral edema | 3% | 1% |
| Pruritus | 3% | 0% |
| Stomach discomfort | 2% | 0% |
The adverse reactions seen in controlled and open-label studies are presented below in the following manner: most common (≥ 5%), common (≥ 1% to < 5%), and less common (< 1%).
The most common adverse reactions (≥ 5%) reported by patients treated with buprenorphine transdermal system in the clinical trials were nausea, headache, application site pruritus, dizziness, constipation, somnolence, vomiting, application site erythema, dry mouth, and application site rash.
The common (≥ 1% to < 5%) adverse reactions reported by patients treated with buprenorphine transdermal system in the clinical trials organized by MedDRA (Medical Dictionary for Regulatory Activities) System Organ Class were:
Gastrointestinal disorders: diarrhea, dyspepsia, and upper abdominal pain
General disorders and administration site conditions: fatigue, peripheral edema, application site irritation, pain, pyrexia, chest pain, and asthenia
Infections and infestations: urinary tract infection, upper respiratory tract infection, nasopharyngitis, influenza, sinusitis, and bronchitis
Injury, poisoning and procedural complications: fall
Metabolism and nutrition disorders: anorexia
Musculoskeletal and connective tissue disorders: back pain, arthralgia, pain in extremity, muscle spasms, musculoskeletal pain, joint swelling, neck pain, and myalgia
Nervous system disorders: hypoesthesia, tremor, migraine, and paresthesia
Psychiatric disorders: insomnia, anxiety, and depression
Respiratory, thoracic and mediastinal disorders: dyspnea, pharyngolaryngeal pain, and cough
Skin and subcutaneous tissue disorders: pruritus, hyperhidrosis, rash, and generalized pruritus
Vascular disorders: hypertension
Other less common adverse reactions, including those known to occur with opioid treatment, that were seen in < 1% of the patients in the buprenorphine transdermal system trials include the following in alphabetical order:
Abdominal distention, abdominal pain, accidental injury, affect lability, agitation, alanine aminotransferase increased, angina pectoris, angioedema, apathy, application site dermatitis, asthma aggravated, bradycardia, chills, confusional state, contact dermatitis, coordination abnormal, dehydration, depersonalization, depressed level of consciousness, depressed mood, disorientation, disturbance in attention, diverticulitis, drug hypersensitivity, drug withdrawal syndrome, dry eye, dry skin, dysarthria, dysgeusia, dysphagia, euphoric mood, face edema, flatulence, flushing, gait disturbance, hallucination, hiccups, hot flush, hyperventilation, hypotension, hypoventilation, ileus, insomnia, libido decreased, loss of consciousness, malaise, memory impairment, mental impairment, mental status changes, miosis, muscle weakness, nervousness, nightmare, orthostatic hypotension, palpitations, psychotic disorder, respiration abnormal, respiratory depression, respiratory distress, respiratory failure, restlessness, rhinitis, sedation, sexual dysfunction, syncope, tachycardia, tinnitus, urinary hesitation, urinary incontinence, urinary retention, urticaria, vasodilatation, vertigo, vision blurred, visual disturbance, weight decreased, and wheezing.