The phrase "used up" is commonly used to describe something that has been depleted or exhausted. There are several synonyms that can be used in place of this phrase, depending on the context. "Depleted," "exhausted," and "spent" are all synonyms for "used up" that can be used to describe resources or energy. "Consumed," "worn out," and "drained" are all synonyms that can be used to describe physical items that have been used to the point of being unusable or obsolete. Regardless of the synonym used, the meaning remains the same: something that has been fully utilized and cannot be used again.