Hepatotoxicity
Zafirlukast can also cause rare but serious side effects like acute liver injury. Zafirlukast-induced hepatotoxicity generally occurs within the first 2–6 months of initiating therapy, though cases have been reported up to 13 months after starting zafirlukast. Zafirlukast-induced hepatotoxicity is characterized by a spectrum of liver damage symptoms, including fatigue, nausea, and right upper quadrant pain followed by dark urine, jaundice and pruritus. Liver enzyme elevations are common, and the pattern usually reflects hepatocellular damage, resembling acute viral hepatitis. It is unclear how the hepatotoxicity occurs, but it may be due to a metabolic intermediate of zafirlukast, since it is metabolized in the liver through the enzyme CYP2C9. When it does occur it can be fatal, and reexposure with zafirlukast may result in a worse injury. Switching zafirlukast to another medication in the same class (e.g. montelukast) or in the related class of 5-lipoxygenase inhibitors can be attempted, but caution should be employed.According to the "Dear Health Care Provider" letter from AstraZeneca, zafirlukast-induced hepatotoxicity has occurred predominantly in females. Churg-Strauss syndrome
Several cases of Churg-Strauss syndrome, also known as allergic angiitis and granulomatosis, have been reported with the use of zafirlukast, montelukast, pranlukast, and other asthma medications. When Churg-Strauss syndrome occurs, it tends to occur in people with long-standing asthma and sinus inflammation, chronic oral corticosteroid use, and the recent initiation of a new anti-asthma therapy (like zafirlukast) in conjunction with tapering the corticosteroids.
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Gigantism Clinical Trials from U.S. National Institutes of Health
Gigantism information from U.S. National Library of Medicine, U.S. Department of Health and Human Services & the National Institutes of Health 
Epidemiology of acromegaly from Pubmed.gov US National Library of Medicine & National Institutes of Health