The first of those goals, civilian rule, is the most immediate. The protesters may have forced out Mr. al-Bashir, but they still have to contend with the junta of generals that quickly declared itself in charge, at least for the time being.

The doctors’ activism and the government’s antagonism have deep historical roots.

Mr. al-Bashir’s regime regarded doctors with suspicion going back to 1989, when an Islamist-backed coup delivered him to power. Some of the earliest organized resistance came from doctors, who organized a strike. The government rounded up those involved: One died in custody from a blow to the head, and another was sentenced to death before an international outcry led to his release.

“Ever since then, the government, of course, had this opinion that doctors are against the government,” the man sentenced to die, Dr. Mamoun Hussein, said in a phone interview. “So their treatment of doctors was according to this concept,” said Mr. Hussein, now 84.

Amid the cronyism and repression of Mr. al-Bashir’s government, many Sudanese doctors left the country. According to one estimate, more work abroad than in Sudan.

Some doctors who stayed behind aligned with the regime, growing wealthy and leapfrogging over colleagues for top jobs. But deteriorating conditions also fostered discontent and led many others to speak out.

One gastroenterologist, Nada Abdalla, 48, spent more than a decade as a doctor in England before returning to Sudan several years ago.