Methylamphetamine also known as Methamphetamine Drug Driving Limit = 10 µg/L
Methamphetamine a potent central nervous system (CNS) stimulant that is used as a recreational drug and, rarely, to treat attention deficit hyperactivity disorder (ADHD) and obesity.
Recreationally, methamphetamine is used to increase sexual desire, lift the mood, and increase energy, allowing some users to engage in sexual activity continuously for several days straight.
In low doses, methamphetamine can cause an elevated mood and increase alertness, concentration, and energy in fatigued individuals. At higher doses, it can induce psychosis and cerebral hemorrhage. Methamphetamine is known to have a high potential for abuse and addiction. Heavy recreational use of methamphetamine may result in psychosis or lead to post-withdrawal syndrome, a withdrawal syndrome that can persist for months beyond the typical withdrawal period.
Unlike amphetamine, methamphetamine is neurotoxic to humans, damaging both dopamine and serotonin neurons in the Central Nervous System.[i] Contrary to the long-term use of amphetamine, there is evidence that methamphetamine causes brain damage from long-term use in humans.
The physical effects of methamphetamine can include loss of appetite, hyperactivity, dilated pupils, flushed skin, excessive sweating, increased movement, dry mouth and teeth grinding (leading to “meth mouth”), headache, irregular heartbeat (usually as accelerated heartbeat or slowed heartbeat), rapid breathing, high blood pressure, low blood pressure, high body temperature, diarrhoea, constipation, blurred vision, dizziness, twitching, numbness, tremors, dry skin, acne, and pale appearance.
The psychological effects of methamphetamine can include euphoria, changes in libido, alertness, apprehension, concentration, decreased sense of fatigue, insomnia or wakefulness, self-confidence, sociability, irritability, restlessness, grandiosity and repetitive and obsessive behaviors. Methamphetamine use also has a high association with anxiety, depression, methamphetamine psychosis, suicide, and violent behaviors. Methamphetamine also has a very high addiction risk.
Following oral administration, methamphetamine is well-absorbed into the bloodstream, with peak methamphetamine concentrations achieved in approximately 3.13–6.3 hours post ingestion. Methamphetamine is also well absorbed following inhalation and following intranasal administration.