Mr. Khan, who took office last August, was a vociferous critic of the I.M.F. as an opposition politician, and during last year’s election campaign he vowed not to turn to it for assistance. But he has been forced to break that pledge — even while promising a sweeping expansion of social welfare programs that would contradict the global body’s insistence on austerity.

Among other belt-tightening moves, the bailout package is expected to lead to cuts in fuel subsidies, putting more burdens on a struggling population. The government has already cut some subsidies and taken other measures the I.M.F. was expected to demand, like depreciating the currency and tightening fiscal and monetary policy. Such moves are likely to be a further drag on growth.

Mr. Khan’s rivals have seized the chance to tie him to the pain that the bailout is likely to bring, referring to his government as P.T.I.M.F. — a play on P.T.I., the initials of Mr. Khan’s political party, and a reference to the fact that top members of his current economic team have worked for the I.M.F. in the past.

In the last stages of the bailout talks, Mr. Khan replaced almost all the top members of that team, most notably Asad Umar, a popular politician with a populist bent who was removed as finance minister last month. Mr. Umar, who was involved in the I.M.F. talks, has said that he was not prepared to inflict pain on the Pakistani people to meet the fund’s requirements. He also opposes the privatization of state-run enterprises, something that the I.M.F. often demands of countries that receive bailouts.

The new adviser to the prime minister on finance, Abdul Hafeez Shaikh, who has the powers of finance minister, has worked for both the I.M.F. and the World Bank. Mr. Khan also recently appointed a former I.M.F. employee, Dr. Reza Baqir, as head of Pakistan’s central bank.