Al-Zuhri (may Allah have mercy on him) said that Sa'd bin Abi Waqqas (may Allah be pleased with him) and Sayyidah Aishah (may Allah be pleased with her) saw no harm in drinking while standing, and both of them would drink while standing. It is also reported from Abu Bakrah (may Allah be pleased with him) that he too would drink while standing.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصداق / 14650