Aspirin is a nonsteroidal anti-inflammatory drug. Aspirin is unique in this class of drugs because it irreversibly inhibits both COX-1 and COX-2 activity by acetylating a serine residue (Ser529 and Ser516, respectively) positioned in the arachidonic acid-binding channel, thus inhibiting the synthesis of prostaglandins and reducing the inflammatory response. The drug is used either alone or in combination with other compounds for the treatment of pain, headache, as well as for reducing the risk of stroke and heart attacks in patients with brain ischemia and cardiovascular diseases.

Propoxyphene is a centrally acting opiate analgesic. Propoxyphene is an odorless, freely soluble in water, white crystalline powder with a bitter taste. In vitro studies demonstrated propoxyphene and the metabolite norpropoxyphene inhibit sodium channels (local anesthetic effect) with norpropoxyphene being approximately 2 fold more potent than propoxyphene and propoxyphene approximately 10 fold more potent than lidocaine. Propoxyphene and norpropoxyphene inhibit the voltage-gated potassium current carried by cardiac rapidly activating delayed rectifier (hERG) channels with approximately equal potency. It is unclear if the effects on ion channels occur within therapeutic dose range. Propoxyphene is indicated for the relief of mild to moderate pain.

Bezitramide was developed as an orally long-acting analgesic compound and was marketed under the brand name Burgodin. The overdose of this drug caused death that is why it was withdrawn from the market.