President Trump on Thursday announced a slew of punishing tariffs on pharmaceuticals, heavy trucks, kitchen cabinets, bathroom vanities and upholstered furniture, saying import taxes on those products would go into effect on Oct. 1.

The tariffs range from 25 percent to 100 percent, with the highest levies applying to “any branded or patented” pharmaceutical product coming into the United States. That decision poses considerable political risk, given that Americans could face higher prices for drugs, as countries pull back from exporting them into the United States.

Mr. Trump said exceptions would be made for pharmaceutical companies that are building manufacturing facilities in the United States and have already broken ground.

This year, as Mr. Trump has repeatedly threatened to impose tariffs on imported medicines, most of the largest brand-name drugmakers have announced plans to spend billions of dollars building or expanding U.S. factories. It is unclear how quickly those projects can proceed.

Mr. Trump, who turned to social media to announce the new tariffs, said the moves would protect American producers from “unfair outside competition.” He said his actions were justified by “large scale ‘FLOODING’” of the products into the United States by other countries.

“It is a very unfair practice, but we must protect, for National Security and other reasons, our Manufacturing process,” Mr. Trump wrote.

Higher costs from the new tariffs will be felt across sectors of the economy, from housing and health care to logistics. The president also said the United States would begin imposing a 50 percent tariff on imported kitchen cabinets, bathroom vanities and associated products, along with a 30 percent tariff on imported furniture and a 25 percent tariff on foreign trucks.

The tariffs will be issued under a national security related law, known as Section 232, that Mr. Trump has used to issue tariffs on steel, aluminum, cars and copper. On Wednesday, the Trump administration announced that it was beginning new investigations under the law into imports of robotics, industrial machinery and medical devices, which could result in tariffs.