How does the author use the Greek word "pharmakon" in the text?

The Greek word “pharmakon” and its mixed meaning symbolize the dangerous duality in every solution the speaker seeks for her depression, and form part of the motif of doubles and cycles in the poem. “Pharmakon” roughly means “drug,” but it can be translated as both “poison” and “cure” (#181). Nelson uses this language of “disease,” “drug,” “poison,” “cure,” and “pharmakon” to refer to everything from writing poetry to sex with the prince of blue to her love of the color blue.