Recently a reader of Psychiatry
On-Line contacted me to share that he had read a case report in this very
electronic journal describing a possible bupropion-alcohol
interaction (1). He went on to describe that while taking bupropion he
quickly lost interest in drinking coffee noting an almost repulsive taste
similar to what my patients described about the taste of alcohol while taking
bupropion. Was it due to nausea, which is a possible side effect associated with
bupropion or due to an alteration in neurochemistry?
Caffeine, not a drug of abuse, but certainly a
substance which can cause a physical dependence is consumed by at least 80% of
adults in the United States on a daily basis (2). The mechanism by which
caffeine seems to exert its effects is by a number of methods including
increasing norepinephrine secretion, inhibiting breakdown of cyclic 3,5
adenosine monophosphate in high concentrations, sensitizing central
catecholamine postsynaptic receptors, enhancing guanosine 3,5, monophosphate,
modulating acetylcholine and serotonin activity and antagonizing central nervous
system adenosine receptors (2). This last mechanism appears to be the key
mechanism. The adenosinergic pathways form a diffuse system, which is considered
depressant within the CNS (2). Caffeine is an adenosine antagonist and can
produce increased dopaminergic transmission within the brain (3). Due to the
increased dopaminergic activity due to its competitive action with adenosine
caffeine could possibly produce behavioral effects similar to other dopaminergic
mediated stimulants (4). Bupropion, which is commonly utilized as a
pharmacologic agent in tobacco cessation, is felt to exert its effects through
dopaminergic release from the nucleus accumbens traveling along the mesolimbic
pathway to the prefrontal cortex (5). This is the pathway proposed to be the
reward pathway of other substances including nicotine, cocaine, amphetamines,
marijuana and alcohol (6). Could caffeine be added to that list? Further studies
will be needed to say definitively but it certainly looks promising.
REFERENCES
1.
Berigan TR, Harazin JS. Bupropion Related Alcohol Cessation. Psychiatry
On-Line
2.
Greden JF, Walters A. Caffeine. In: Substance Abuse A Comprehensive
Textbook 3rd Edition. Edited by Lowinson JH, Ruiz P, Millman RB,
Langrod JG. Baltimore, Williams and Wilkins, 1997 PP 297-8
3.
Ferre S. Adenosine-dopamine interactions in the ventral striatum.
Implications for the treatment of schizophrenia. Psychopharmacology (Berl) 1997
Sep; 133(2):107-20
4.
Garrett BE, Griffiths RR. The role of dopamine in the behavioral effects
of caffeine in animals and humans. Pharmacol Biochem Behav 1997 Jul;57(3):533-41
5.
Valenzuela CF, Harris RA. Alcohol: Neurobiology. In: Substance Abuse A
Comprehensive Textbook 3rd Edition. Edited by Lowinson JH, Ruiz P,
Millman RB, Langrod JG. Baltimore, Williams and Wilkins, 1997 pg. 130
6.
Lesher AI. Understanding Drug Addiction: Implications for Treatment.
Hospital Practice 1996 Oct:47-59