6 ADVERSE REACTIONS The following adverse reactions are discussed in more detail in other sections of the labeling: Myocardial ischemia, myocardial infarction, and Prinzmetal’s angina [see Warnings and Precautions ( 5.1 ) ] Arrhythmias [see Warnings and Precautions ( 5.2 ) ] Chest, throat, neck, and/or jaw pain/tightness/pressure [see Warnings and Precautions ( 5.3 ) ] Cerebrovascular events [see Warnings and Precautions ( 5.4 ) ] Other vasospasm reactions [see Warnings and Precautions ( 5.5 ) ] Medication overuse headache [see Warnings and Precautions ( 5.6 ) ] Serotonin syndrome [see Warnings and Precautions ( 5.7 ) ] Increase in blood pressure [see Warnings and Precautions ( 5.8 ) ] Hypersensitivity reactions [see Contraindications ( 4 ) and Warnings and Precautions ( 5.9 ) ] Seizures [see Warnings and Precautions ( 5.10 ) ] Most common adverse reactions (≥5% and > placebo) were injection site reactions, tingling, dizziness/vertigo, warm/hot sensation, burning sensation, feeling of heaviness, pressure sensation, flushing, feeling of tightness, and numbness. (6.1) To report SUSPECTED ADVERSE REACTIONS, contact Endo Pharmaceuticals at 1-800-462-3636 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 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 with rates in the clinical trials of another drug and may not reflect the rates observed in practice. Migraine Headache: Table 1 lists adverse reactions that occurred in 2 US placebo-controlled clinical trials in migraine subjects [see Clinical Studies ( 14.1 ) ] following either a single 6 mg dose of sumatriptan injection or placebo. Only reactions that occurred at a frequency of 2% or more in groups treated with sumatriptan injection 6 mg and that occurred at a frequency greater than the placebo group are included in Table 1. Table 1. Adverse Reactions Reported by at Least 2% of Subjects and at a Greater Frequency Than Placebo in 2 Placebo-Controlled Migraine Clinical Trialsa Percent of Subjects Reporting Adverse Reaction Sumatriptan Injection 6 mg Subcutaneous (n = 547) Placebo (n = 370) Atypical sensations Tingling Warm/hot sensation Burning sensation Feeling of heaviness Pressure sensation Feeling of tightness Numbness Feeling strange Tight feeling in head 42 14 11 7 7 7 5 5 2 2 9 3 4 <1 1 2 <1 2 <1 <1 Cardiovascular Flushing 7 2 Chest discomfort Tightness in chest Discomfort: nasal cavity/sinuses 5 3 2 1 <1 <1 Injection site reactionb 59 24 Miscellaneous Jaw discomfort 2 0 Musculoskeletal Weakness Neck pain/stiffness Myalgia 5 5 2 <1 <1 <1 Neurological Dizziness/vertigo Drowsiness/sedation Headache 12 3 2 4 2 <1 Skin Sweating 2 1 a The sum of percentages cited is greater than 100% because subjects may have experienced more than 1 type of adverse reaction. Only reactions that occurred at a frequency of 2% or more in groups treated with sumatriptan injection and occurred at a frequency greater than that of the placebo group are included. b Includes injection site pain, stinging/burning, swelling, erythema, bruising, bleeding. The incidence of adverse reactions in controlled clinical trials was not affected by gender or age of the subjects. There were insufficient data to assess the impact of race on the incidence of adverse reactions. Cluster Headache: In the controlled clinical trials assessing the efficacy of sumatriptan injection as a treatment for cluster headache [see Clinical Studies ( 14.2 ) ], no new significant adverse reactions were detected that had not already been identified in trials of sumatriptan in subjects with migraine. Overall, the frequency of adverse reactions reported in the trials of cluster headache was generally lower than in the migraine trials. Exceptions include reports of paresthesia (5% sumatriptan, 0% placebo), nausea and vomiting (4% sumatriptan, 0% placebo), and bronchospasm (1% sumatriptan, 0% placebo).