Coffee could help ease the symptoms of cocaine addiction, a new study has revealed.
Caffeine can block the changes in the brain associated with cocaine use, researchers found.
They said the findings are particularly useful for women, who are more prone to cocaine addiction than men, The Daily Mail reported.
They found that cocaine shifts the menstrual cycle, changing a women’s level of oestrogen – the female sex hormone.
Previous research has shown when oestrogen levels are high, women are more susceptible to cocaine.
Women are already known to be more sensitive to the effects of the drug in general, and show a response to the drug at a much lower dose than men.
This makes them much more susceptible to cocaine abuse and addiction,than men.
But the researchers discovered caffeine blocks the changes, restoring the female cycle, and easing the symptoms of addiction.
The New York-based scientists said: ‘Cocaine induced seemingly random changes in the estrus cycle - the name given to animals' menstrual cycle.
'This was not seen following caffeine administration.
‘Furthermore, combination of cocaine and caffeine did not alter the estrus cycle.
‘The cocaine-induced changes were blocked by caffeine.’
Professor Patricia Broderick, editor-in-chief of the Journal of Caffeine Research and lead author of the study, said: 'This is cutting-edge work that has never been shown before.
'It is critical knowledge relevant to women's reproductive health.'
As part of the study, researchers examined vaginal smears from rats to determine which stage of their estrus cycle they were at.
Smears were taken immediately before and after the rats had taken cocaine, caffeine, or both at once.
Cocaine induced seemingly random changes in the estrus cycle, the researchers found.
But this effect was not seen if the rats were given caffeine 30 minutes after cocaine.
Furthermore, a combination of cocaine and caffeine did not alter the rats' estrus cycle.
They concluded that caffeine blocks the changes to the brain induced by cocaine.
This adds to their earlier research, which found caffeine can help with cocaine addiction.
Cocaine stimulates the releases the happy hormone dopamine in the brain, which creates a euphoric feeling of reward, and can lead to addiction.
But caffeine affects the adenosine system, which is involved in promoting sleep and waking, by stimulating adenosine receptors.
Adenosine regulates dopamine levels in the brain, decreasing the symptoms of addiction.