Pramoxine, also known as pramocaine, is different from other local anesthetic compounds in chemical structure. Active groups which are carboxylic acid derivatives like ester and amide are not present in this molecule. The drug molecule consists of ether functional groups that are much less active on a chemical level. The presence of the free radical morpholine in this compound is the cause of the reduction of the factor of toxicity and pharmacological activity. In pramoxine, toxicity is reduced but the local anesthetic affect is maintained.
Pramoxine is a local anesthetic drug used for topical anesthesia. Hydrochloride salt is preferred because of its easy dissolution in water, thus the drug is readily absorbed through the skin. Topical anesthetics are drugs used for removing pain and itching induced by sun burn or other minor burns, insect bites, poisonous plants and minor cut and scratch conditions.
Pramoxine, like other local anesthetics, reduces permeability of sodium ions in neuronal membranes, blocks to start and to improve neuronal impulses and thus inhibits depolarization of neurons. Pramoxine relieves itching by affecting on the neuronal membrane of the end of neurons without myelin layer. The characteristic chemical structure of pramoxine is responsible for minimum cross-sensitization. Pramoxine rarely causes skin sensitivity so it is preferred as a topical anesthetic drug. It is used for an antipruritic drug as well. It can reduce the sense of itching by blocking transfer of impulses along fibers of sensor neurons. However, the anesthetic effect of pramoxine is not the direct cause of the antipruritic effect. This is because this effect only appears on the cold pain threshold and is a hypoalgesic affect.
