The young man's death raised to 32 the number of people killed in a month of demonstrations against the socialist leader's government and his plan to rewrite the constitution.
Government forces used tear gas against demonstrators in las Mercedes, on Caracas' east end, the prosecutor's office said.
At least one protester caught fire and two opposition lawmakers were among various people injured, AFP reporters at the scene said.
It was not yet clear if that person was the man who died.
"The (deceased) young man sustained serious neck trauma that sent him into shock and then heart failure," Gerardo Blyde, mayor of the capital's Baruta district, said without specifying what struck the victim.
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The opposition accuses the elected president of maneuvering to strengthen his grip on power. He has for months been resisting calls for a vote on removing him from office as the oil-rich nation staggers under food shortages, a near- crippled state-run economy and one of the world's highest inflation rates.
Clouds of grey smoke from tear gas canisters filled the air as police with riot shields and trucks advanced along a major avenue in the east of the capital.
Protesters were enraged by the socialist president's launching of procedures by the electoral council to draw up a new constitution.
"I am convening a national constituent assembly of citizens with deep popular involvement so that our people... with their voice can decide the destiny of our homeland," he said in a speech at the council.
Private polls indicate that more than 70 percent of those interviewed do not support Maduro, who was elected in 2013 to succeed his late mentor Hugo Chavez.
His center-right opponents and some international powers said the move is an attempt to dodge local elections this year and a presidential poll set for late 2018.