Blood Pressure Drug Could Fight Cocaine Addiction

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The newest treatment for cocaine addiction may come from a drug that’s already being used to battle high blood pressure and is showing some experimental benefits in treating  post-traumatic stress disorder (PTSD) as well. That, at least, is what some new research in rats shows.

Like humans, rats learn to associate the positive experience of cocaine with environmental cues, such as the features of the place  they get the drug.  If they are repeatedly given coke in a particular spot, they tend to hang out more in that spot, like human addicts waiting for their man.

But rats given the blood-pressure-lowering drug propranolol before being allowed to enter the cage in which they’d previously gotten cocaine injections no longer preferred that cage to another one where they’d never gotten high.  And those given saline instead of propranolol still went for the place where they’d gotten coke. This effect lasted at least two weeks, suggesting that it may have  adjusted the rats’ memories of cocaine in more than just a fleeting way.

Does this mean that the rats no longer liked cocaine — or simply that they couldn’t remember whether they liked it or not, or even that they remembered it and liked it but no longer linked venue to experience?  Since rats can’t talk that’s impossible to say, and even in humans, propranolol’s mechanism is unclear. Research has shown mixed results in determining its effectiveness in preventing or treating PTSD, though the fears of some medical ethicists that the drug would simply replace life-altering memories with amnesia have not been borne out.

Rather, the drug simply seems to make those memories less vivid and intrusive. (In rats, the likelihood is higher that any recollection of an experience would actually be wiped clean. Since rats don’t have verbal memories, removing the connection between an event and pleasure or fear might completely prevent recall.)

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What this means for humans being treated for cocaine addiction is that while a history of abusing the drug might forever remain fresh in memory, the pleasant associations — the thrill of the score, the anticipation of the high, the first rush of the drug — would be dulled. With that may go the cravings, and without cravings, the risk of a lapse into using is reduced as well. Studies of propranolol have so far have yielded only modest evidence that the drug can work this way, but modest is better than nothing.  And curiously, one study found that people given propranolol while undergoing cocaine withdrawal had better verbal recall, suggesting that the drug indeed affects memory only selectively.

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Unlike opioid addiction or alcoholism, both of which can be at least partly battled with medications, cocaine addiction still must be treated entirely with non-pharmacological weapons.  Since propranolol is already FDA-approved for treating hypertension, it’s certainly worth more investigation for cocaine treatment. The new research was published in the journal Neuropsychopharmacology.

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