If anyone has any access to databases that can describe the histo...

If anyone has any access to databases that can describe the history of drug licensing in other countries and whether Merck had to amend product statements, this is worth investigating. I do know that montelukast was at least not initially licensed for seasonal allergies in the United Kingdom when the FDA granted approval in the US. As of 2006, seasonal allergies were not on the approved listed in the UK. More to add to the files: Safety of leukotriene antagonists United Kingdom — The Medicines Control Agency has published a review of adverse drug reactions to a new class of asthma drugs, leukotriene antagonists. Zafirlukast and moltelukast, competitive cysteinyl leukotriene type-1 receptor antagonists, were both marketed for the first time in 1998. Cysteinyl leukotrienes are inflammatory mediators and potent constrictors of bronchial smooth muscle that attract human eosinophils and cause airway oedema, mucus hypersecretion and reduced mucociliary clearance. By blocking this action, leukotriene antagonists can improve respiratory function and lessen symptoms in patients with asthma. The pharmacological action of leukotrienes is quite complex and varying side effects have been reported. Zafirlukast inhibits the hepatic cytochrome P4502C9, and interacts with warfarin, theophyllin, terfenadine, acetylsalicylic acid and erythromycin. Montelukast is metabolized by hepatic cytochrome P450CYP3A4 and co-administration of such drugs as phenytoin, phenobarbitone and rifampicin, which induce this enzyme, result in a marked reduction in plasma levels. Side-effects identified during clinical trials were headache, abdominal pain, nausea, diarrhoea, gastro-enteritis, influenza, pharyngitis, sinusitis, cough, nasal congestion, dizziness, fatigue and insomnia. Since marketing of montelukast, 173 reports of 317 suspected adverse drug reactions have been received in the United Kingdom. These include oedema (50), psychiatric reactions, including including agitation/restlessness (15), allergy, including anaphylaxis, angioedema and urticaria (10), chest pain (7), tremor (5), mouth dryness (5), vertigo (4) and arthralgia (3). Reference: Current Problems in Pharmacovigilance, Volume 24, August 1998. https://www.who.ch/druginformation/vol12/12-4.pdf