"This is an extremely worrisome decision and conflicts with the larger public interest... Last November, the Prime Minister's Office had expressed concern over rising drug prices and, hence, the latest move by the government doing the opposite is confounding," Patel said in a letter to Finance Minister Arun Jaitley.
He said it is "baffling" why the government has chosen to withdraw exemptions from these medicines given that a large number of these are included in the National Essential Medicines List, 2015.
"My state Gujarat is home to a large number of haemophilia patients," said Patel.
The recent changes in the duty will impose an additional burden on patients and jeopardise their well-being, he said.
Noting that 2015-16 has seen increased tax collections, particularly due to the "windfall gains" from falling oil prices, Patel urged Jaitley to revoke the decision.
The Central Board of Excise and Customs (CBEC) had last week issued a notification withdrawing exemption from levy of basic customs duty on as many as 74 drugs, including life- saving medicines used for treating cancer and HIV. The move is expected to lead to a sharp rise in their prices.