GlaxoSmithKline P.L.C. has agreed to a $1 billion settlement that will cover 800 claims that the company’s drug Paxil causes birth defects. The company paid $2.5 million to a Pennsylvania boy who allegedly suffers from severe heart defects because of Paxil. Glaxo has set aside a total of $2.4 billion to settle various lawsuits involving Paxil and the company’s diabetes drug Avandia