Australian National University researchers have developed a computer model that determines how pain relief drugs like anaesthetics work on the body.

Dr Ben Corry and Lewis Martin from Research School of Biology said that the model discloses for the first time how benzocaine (a local anaesthetic) and phenytoin (an anti-epilepsy drug) enter the nerve cells and prevent the transmission of pain signals to the brain.

Researchers said that local anaesthetics, based on cocaine, are being used for more than 100 years now. However, the mechanism behind the drug effect has not yet been determined until now.

They said that the finding helps to create new drugs without the side-effects that existing drugs bring along.

"By understanding how the current range of drugs work we can best design the next generation, to better treat conditions such as chronic pain, epilepsy and cardiac arrhythmia," said Corry in a statement.

For the study, the researchers used over three million CPU hours on the National Computational Infrastructure's supercomputer to simulate the drug's journey to the nerve cell.

When pain signals are transmitted to the brain, proteins in nerve cell walls open that allows sodium and potassium ions to enter. Meanwhile, the simulation showed that the drug's final binding site is inside the sodium gateway protein, wherein it blocks the channel and thereby averts the signal transmission.

Researchers said that pain relief drugs are also simultaneously used for nerve-signal disorder treatments like epilepsy or heart arrhythmia. However, current drugs extensively target sodium channels throughout the body that can cause side-effects.

"Knowledge of the fine molecular detail of the drug opens up possibilities to conceive new drugs," said Corry.

The finding is published in the Journal PLOS Computational Biology.