Opiate and Alcohol
A lot of people that are overdosed are not from a single drug alone but instead from more than one drug.
The important thing is, there is no single drug present in those cases that can be a lethal dose, rather, it is the chemistry effect of combining different drugs that made it lethal. A lot of overdose cases involve legal drugs, for example, combining opiates like heroin and prescription painkillers with alcohol can be extremely dangerous for the one who’s taking it as both substances suppress the lung muscles and breathing rhythm but by different ways.
In the United States of America, the cause of most deaths by overdose compared to any single drug is prescription opiates. A lot of these deaths eventually result from the failure of the respiratory system. A dose of toxic opiate dramatically increases the effect of GABA, which makes breathing slow down and finally stop.
An overdose of Alcohol mainly happens from two things:
First, alcohol induces unconsciousness. It can slow or even stop breathing if taken at high levels.
Second, since the body has it’s built-in mechanism of removing toxic from within by vomiting, it will empty the stomach from unabsorbed alcohol. If this happens while being unconscious, there is a high possibility that the person will drown from inhaling the vomit
Cigarette smoking can kill by causing the user to have lung cancer, but smoking alone cannot lead to nicotine overdose. On the other hand, it is possible to overdose on nicotine if someone uses a combination of gums with nicotine or any other source of nicotine plus cigarette smoking at the same time. The combination allows a lot of nicotine into the body than just smoking alone. Nicotine can also paralyze the muscles that are responsible for controlling the breathing and may cause a heart attack if taken at really high levels.
Cocaine and Stimulants
Meth, cocaine, and any other stimulants trigger the release of a somewhat adrenaline-like hormone that causes an increase in activity, increase in heart rate, increase in blood pressure, and narrowing of the blood vessels.
Cocaine is also a death specialist and can kill a human in a variety of ways. A few examples of how people die from cocaine overdose is a heart attack, increase in temperature or hyperthermia, and brain damage. Even taking a low dosage of cocaine, the risks of having a heart attack are elevated to a certain extent.
Stimulants like amphetamine, meth, ecstasy increase the levels of neurotransmitter dopamine and norepinephrine, which causes heart attack, hyperthermia, and brain damage. These “club drugs” are often used in a hot, overcrowded conditions like dancing areas. The most common ecstasy overdose makes the body overheat.