Food and Drug Administration Commissioner Marty Makary was supposed to be one of President Donald Trump’s more conventional, qualified personnel picks, with sterling academic credentials and bipartisan support. But just over a year into his tenure, those inside the agency that regulates roughly one-fifth of consumer spending in the U.S. describe a culture rocked by staff clashes, leadership turmoil, industry backlash and an embattled, paranoid leader. Outside, drug companies say they’ve been blindsided by setbacks. Some people familiar with the dynamics called the situation unsustainable. While no immediate ouster is planned, people familiar with the matter who requested anonymity to discuss personnel matters say one more high-profile misstep could put his job at risk.  Makary, 55, and his allies defend his record, pointing to his successful moves to reduce synthetic food dyes, crack down on misleading television ads and streamline drug approvals.…