Tips på hur man lättare kan hålla sig vaken!

"This crossover of the symptoms of both drugs is what can sometimes lead to a fatal overdose, causing the abuser to believe they are less high or more tolerant than they really are, which can sometimes prompt them to take more of one or both drugs.

While there are many dangers that come with combining heroin and cocaine, the most common cause of death from a speedball comes from a delayed overdose response to the stimulant. Because the effects of stimulants such as cocaine wear off more quickly than the effects of depressants like heroin, a user may attempt another dose of cocaine to get back to their previous high.

This additional dose of cocaine can lead to a fatal opioid overdose by causing the user to feel a false sense of stability from using the two drug simultaneously. The effects of this delayed overdose cannot be felt by the user until it is too late."

"These mixtures are often more potent than the sum of their parts, through drug synergy"

samt:

"and the use of stimulants both to potentiate the opioid and combat somnolence caused by high and rapidly escalating doses"

"Recent studies by Foltin, Fischman and colleagues and by Walsh and colleagues have evaluated the acute subjective and physiological effects of cocaine in combination with opioid mu agonists. The subjective effects of various dose combinations of mu agonists and cocaine were greater than those produced by either drug alone on measures such as "drug liking" and "high". The qualitative profile of subjective effects produced by the opioid/cocaine combination was roughly equivalent to the sum of effects produced by the two drugs singly, rather than producing novel or unique subjective effects. The cardiovascular effects of cocaine, including tachycardia and pressor action, were enhanced when cocaine was administered in the presence of the mu agonist. Other studies have compared the effects of cocaine in opioid-dependent subjects during chronic maintenance on mu opioid agonists. In studies of methodone-maintained patients, the subjective response to cocaine (e.g., "magnitude of drug effect", "good effect") was significantly greater compared to control subjects. Similarly, some studies in buprenorphine-maintained patients reported that the subjective response to cocaine was either enhanced or not appreciably altered compared to a control condition. Enhanced cardiovascular responses to cocaine were also observed under these chronic opioid dosing conditions. These and other findings suggest that administration of mu agonists generally enhances the effects of cocaine in humans, particularly the positive subjective responses to cocaine."

http://opioids.com/speedballs/index.html

What they seem to conclude is that any mu agonist increases the cardiovascular effects of cocaine. I imagine that since the cocaine is potentiated, people who die from a speedball probably injected what is normally a good dose by itself and it turned out to be a cocaine od. If you read the whole article, they suggest a possible interaction between the opiod peptide system and dopamine (DA) levels in the nucleus accumbens (NA). Apparently, cocaine by itself has a positive effect on the opiod peptide system and heroin has an effect on DA levels in the NA.

"In the present study, we examined the effect of an acute administration of the selective suicide inhibitor of gamma-aminobutyric acid (GABA)-transaminase, gamma-vinyl GABA on increases in nucleus accumbens dopamine produced by a cocaine/heroin challenge in freely moving animals. Cocaine (20 mg/kg, i.p.) produced an elevation in extracellular nucleus accumbens dopamine of approximately 380% above baseline, while heroin produced only a moderate increase of 70%. Coadministration of these two drugs, however, produced a synergistic elevation in nucleus accumbens dopamine of 1000%. This response was reduced by 50% in animals pretreated with gamma-vinyl GABA (300 mg/kg, i.p.) 2.5 h prior to challenge. This same dose of gamma-vinyl GABA inhibited cocaine-induced increases in nucleus accumbens dopamine by 25% and completely abolished heroin-induced increase. These findings indicate that gamma-vinyl GABA can interfere with the synergistic effects produced by the combination of an indirect dopamine releaser (heroin) and a dopamine reuptake blocker (cocaine)."
Gamma-vinyl gamma-aminobutyric acid attenuates the synergistic elevations of nucleus accumbens dopamine produced by a cocaine/heroin(speedball) challenge, Gerasimov MR, Dewey SL, Department of Chemistry, Brookhaven National Laboratory, Upton, NY 11973, USA. Eur J Pharmacol 1999 Sep 3;380(1):1-4
It is probably this huge increase in dopamine levels that increases the morbidity associated with speedballs. I would think that the amount of each drug used is the most important factor. Obviously, a much smaller amount of each will do. It's true that the two drugs blunt some of each other's effects, but mainly its just for the subjective effects (less anxiety, nervousness, shitty comedown from the coke, more awake than usual from the heroin).
"The use of MAO inhibitors or tricyclic antidepressants with hydrocodone preparations may increase the effect of either the antidepressant or hydrocodone."
http://www.erowid.org/pharms/hydroco...e_health.shtml