But lorcaserin has not been tested alongside phentermine, and it was in combination with phentermine that fenfluramine and dexfenfluramine looked worst.

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In 1997, the weight-loss drugs fenfluramine and dexfenfluramine were withdrawn from the market after evidence emerged that they caused heart valve damage.

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These medicines, fenfluramine and dexfenfluramine, caused heart valve damage when used alone and with another drug, phentermine, in the infamous fen-phen combo.

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