Methamphetamine - Adverse Effects - Addiction

Addiction

Methamphetamine is highly addictive. While the withdrawal itself may not be dangerous, withdrawal symptoms are common with heavy use and relapse is common.

Methamphetamine-induced hyperstimulation of pleasure pathways can lead to anhedonia months after use has been discontinued. Investigation of treatments targeting dopamine signalling such as bupropion, or psychological treatments that raise hedonic tone, such as behavioral activation therapy, have been suggested. It is possible that daily administration of the amino acids -tyrosine and -5HTP/tryptophan can aid in the recovery process by making it easier for the body to reverse the depletion of dopamine, norepinephrine, and serotonin. Although studies involving the use of these amino acids have shown some success, this method of recovery has not been shown to be consistently effective.

It is shown that taking ascorbic acid prior to using methamphetamine may help reduce acute toxicity to the brain, as rats given the human equivalent of 5–10 grams of ascorbic acid 30 minutes prior to methamphetamine dosage had toxicity mediated, yet this will likely be of little avail in solving the other serious behavioral problems associated with methamphetamine use and addiction that many users experience. Large doses of ascorbic acid also lower urinary pH, reducing methamphetamine's elimination half-life and thus decreasing the duration of its actions.

To combat addiction, doctors are beginning to use other forms of stimulants such as dextroamphetamine, the dextrorotatory (right-handed) isomer of the amphetamine molecule, to break the addiction cycle in a method similar to the use of methadone in the treatment of heroin addicts. There are no publicly available drugs comparable to naloxone, which blocks opiate receptors and is therefore used in treating opiate dependence, for use with methamphetamine problems. However, experiments with some monoamine reuptake inhibitors such as indatraline have been successful in blocking the action of methamphetamine. There are studies indicating that fluoxetine, bupropion and imipramine may reduce craving and improve adherence to treatment. Research has also suggested that modafinil can help addicts quit methamphetamine use, as can Topiramate.

Methamphetamine addiction is one of the most difficult forms of addictions to treat. Bupropion, aripiprazole, and baclofen have been employed to treat post-withdrawal cravings, although the success rate is low. Modafinil is somewhat more successful, but this is a Class IV scheduled drug. Ibogaine has been used with success in Europe, where it is a Class I drug and available only for scientific research. Mirtazapine has been reported useful in some small-population studies.

As the phenethylamine phentermine is a constitutional isomer of methamphetamine, it has been suggested that it may be effective in treating methamphetamine addiction. Phentermine is a central nervous system stimulant that acts on dopamine and norepinephrine. When comparing (+)-amphetamine, (+/-)-ephedrine, and phentermine, one key difference among the three drugs is their selectivity for norepinephrine (NE) release vs. dopamine (DA) release. The NE/DA selectivity ratios for these drugs as determined in vitro are (+/-)-ephedrine (18.6) > phentermine (6.7) > (+)-amphetamine (3.5).

Abrupt interruption of chronic methamphetamine use results in the withdrawal syndrome in almost 90% of the cases.

The mental depression associated with methamphetamine withdrawal lasts longer and is more severe than that of cocaine withdrawal.