The rupee depreciated by 18 paise to 46.38 against the US currency in early trade on expectations of capital outflows by foreign funds and dollar demand from importers on Thursday.At the Interbank Foreign Exchange (Forex) market, the domestic unit traded 18 paise down at 46.38 a dollar. The rupee ended 10 paise higher at 46.20 against the US currency in the previous session.