The SRD says potions can be administered by others with a full-round action:
Drinking a potion or using an oil is a standard action. The potion or oil takes effect immediately. Using a potion or oil provokes attacks of opportunity.
A character can carefully administer a potion to an unconscious creature as a full-round action, trickling the liquid down the creature's throat.
Can my familiar feed me while I'm conscious and in combat? If so, does it require expenditure of effort larger than a free action by the imbiber? Would the imbiber provoke AoOs? Can I get a drinking tumor?