Acetaminophen and propoxyphene, a weak opioid, are combined in the prescription painkiller Darvocet 500 mg to treat mild to moderate pain. It was originally widely used, but because of major safety issues, like heart toxicity, it is now prohibited in many nations, including the US. In most places, purchasing or taking Darvocet without a doctor's supervision is dangerous and prohibited. For safe options to pain management, always seek advice from a healthcare professional.