ADVERSE REACTIONS
The following adverse reactions are discussed in more detail in other sections of the labeling.
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•Myocardial Ischemia [see Warnings and Precautions (5.1)]
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•Sinoatrial and Atrioventricular Nodal Block [see Warnings and Precautions (5.2)]
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•Atrial Fibrillation/Atrial Flutter [see Warnings and Precautions (5.3)]
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•Hypersensitivity, Including Anaphylaxis [see Warnings and Precautions (5.4)]
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•Hypotension [see Warnings and Precautions (5.5)]
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•Hypertension [see Warnings and Precautions (5.6)]
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•Bronchoconstriction [see Warnings and Precautions (5.7)]
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•Seizure [see Warnings and Precautions (5.8)]
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•Cerebrovascular Accident (Stroke) [see Warnings and Precautions (5.9)]
Clinical Trials Experience
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.
During clinical development, 1,651 subjects were exposed to Lexiscan, with most receiving 0.4 mg as a rapid (≤ 10 seconds) intravenous injection. Most of these subjects received Lexiscan in two clinical studies that enrolled patients who had no history of bronchospastic lung disease as well as no history of a cardiac conduction block of greater than first-degree AV block, except for patients with functioning artificial pacemakers. In these studies (Studies 1 and 2), 2,015 patients underwent myocardial perfusion imaging after administration of Lexiscan (N = 1,337) or Adenoscan® (N = 678). The population was 26–93 years of age (median 66 years), 70% male and primarily Caucasian (76% Caucasian, 7% African American, 9% Hispanic, 5% Asian). Table 1 shows the most frequently reported adverse reactions.
Overall, any adverse reaction occurred at similar rates between the study groups (80% for the Lexiscan group and 83% for the Adenoscan group). Aminophylline was used to treat the reactions in 3% of patients in the Lexiscan group and 2% of patients in the Adenoscan group. Most adverse reactions began soon after dosing, and generally resolved within approximately 15 minutes, except for headache which resolved in most patients within 30 minutes.
Table 1 Adverse Reactions in Studies 1 and 2 Pooled (Frequency ≥ 5%)
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Lexiscan
N = 1,337
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Adenoscan
N = 678
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Dyspnea
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28%
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26%
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Headache
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26%
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17%
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Flushing
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16%
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25%
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Chest Discomfort
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13%
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18%
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Angina Pectoris or ST Segment Depression
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12%
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18%
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Dizziness
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8%
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7%
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Chest Pain
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7%
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10%
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Nausea
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6%
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6%
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Abdominal Discomfort
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5%
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2%
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Dysgeusia
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5%
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7%
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Feeling Hot
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5%
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8%
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ECG Abnormalities
The frequency of rhythm or conduction abnormalities following Lexiscan or Adenoscan is shown in Table 2 [see Warnings and Precautions (5.2)].
Table 2 Rhythm or Conduction Abnormalities
in Studies 1 and 2
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Lexiscan
N / N evaluable (%)
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Adenoscan
N / N evaluable (%)
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Rhythm or conduction abnormalities
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332/1275 (26%)
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192/645 (30%)
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Rhythm abnormalities
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260/1275 (20%)
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131/645 (20%)
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PACs
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86/1274 (7%)
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57/645 (9%)
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PVCs
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179/1274 (14%)
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79/645 (12%)
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First-degree AV block (PR prolongation > 220 msec)
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34/1209 (3%)
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43/618 (7%)
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Second-degree AV block
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1/1209 (0.1%)
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9/618 (1%)
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AV conduction abnormalities (other than AV blocks)
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1/1209 (0.1%)
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0/618 (0%)
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Ventricular conduction abnormalities
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64/1152 (6%)
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31/581 (5%)
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Respiratory Abnormalities
In a randomized, placebo-controlled trial (Study 3) of 999 subjects with asthma (n=532) or stable chronic obstructive pulmonary disease (n=467), the overall incidence of pre-specified respiratory adverse reactions was greater in the Lexiscan group compared to the placebo group (p < 0.001). Most respiratory adverse reactions resolved without therapy; a few subjects received aminophylline or a short acting bronchodilator. No differences were observed between treatment arms in the reduction of >15% from baseline at two-hours in FEV1 (Table 3).
Table 3 Respiratory Adverse Effects in Study 3
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Asthma Cohort
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COPD Cohort
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Lexiscan
(N=356)
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Placebo
(N=176)
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Lexiscan
(N=316)
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Placebo
(N=151)
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Overall Pre-specified Respiratory Adverse Reaction
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12.9%
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2.3%
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19.0%
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4.0%
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Dyspnea
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10.7%
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1.1%
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18.0%
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2.6%
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Wheezing
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3.1%
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1.1%
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0.9%
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0.7%
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FEV1 reduction >15%
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1.1%
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2.9%
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4.2%
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5.4%
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Renal Impairment
In a randomized, placebo-controlled trial of 504 subjects (Lexiscan n=334 and placebo n=170) with a diagnosis or risk factors for coronary artery disease and NKFK/DOQI Stage III or IV renal impairment (defined as GFR 15-59 mL/min/1.73 m2), no serious adverse events were reported through the 24-hour follow-up period.
Post-Marketing Experience
Cardiovascular
Myocardial infarction, cardiac arrest, ventricular arrhythmias, supraventricular tachyarrhythmias including atrial fibrillation with rapid ventricular response (new-onset or recurrent), atrial flutter, heart block (including third-degree block), asystole, marked hypertension, symptomatic hypotension in association with transient ischemic attack, seizures and syncope [see Warnings and Precautions (5.1), (5.2), (5.3), (5.5), (5.6) and (5.8)] have been reported. Some events required intervention with fluids and/or aminophylline [see Overdosage (10)]. QTc prolongation shortly after Lexiscan administration has been reported.
Central Nervous System
Tremor, seizure, transient ischemic attack, and cerebrovascular accident including intracranial hemorrhage [see Warnings and Precautions (5.8) and (5.9)].
Gastrointestinal
Abdominal pain, occasionally severe, has been reported a few minutes after Lexiscan administration, in association with nausea, vomiting, or myalgias; administration of aminophylline, an adenosine antagonist, appeared to lessen the pain. Diarrhea and fecal incontinence have also been reported following Lexiscan administration.
Hypersensitivity
Anaphylaxis, angioedema, cardiac or respiratory arrest, respiratory distress, decreased oxygen saturation, hypotension, throat tightness, urticaria, rashes have occurred and have required treatment including resuscitation [see Warnings and Precautions (5.4)].
Musculoskeletal
Musculoskeletal pain has occurred, typically 10-20 minutes after Lexiscan administration; the pain was occasionally severe, localized in the arms and lower back and extended to the buttocks and lower legs bilaterally. Administration of aminophylline appeared to lessen the pain.
Respiratory
Respiratory arrest, dyspnea and wheezing have been reported following Lexiscan administration.
Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to Lexiscan exposure.
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