Due to the high lipophilicity of methamphetamine, it can readily move through the blood–brain barrier faster than other stimulants, where it is more resistant to degradation by monoamine oxidase. The amphetamine metabolite peaks at 10–24 hours. Methamphetamine is excreted by the kidneys, with the rate of excretion into the urine heavily influenced by urinary pH. When taken orally, 30–54% of the dose is excreted in urine as methamphetamine and 10–23% as amphetamine. Following IV doses, about 45% is excreted as methamphetamine and 7% as amphetamine. The elimination half-life of methamphetamine varies with a range of 5–30 hours, however it is on average 9 to 12 hours in most studies. The elimination half-life of methamphetamine does not vary by route of administration, but is subject to substantial interindividual variability.CYP2D6, dopamine β-hydroxylase, flavin-containing monooxygenase 3, butyrate-CoA ligase, and glycine N-acyltransferase are the enzymes known to metabolize methamphetamine or its metabolites in humans. The primary metabolites are amphetamine and 4-hydroxymethamphetamine; other minor metabolites include: 4-hydroxyamphetamine, 4-hydroxynorephedrine, 4-hydroxyphenylacetone, benzoic acid, hippuric acid, norephedrine, and phenylacetone, the metabolites of amphetamine. Among these metabolites, the active sympathomimetics are amphetamine, 4‑hydroxyamphetamine, 4‑hydroxynorephedrine, 4-hydroxymethamphetamine, and norephedrine. Methamphetamine is a CYP2D6 inhibitor.The main metabolic pathways involve aromatic para-hydroxylation, aliphatic alpha- and beta-hydroxylation, N-oxidation, N-dealkylation, and deamination. The known metabolic pathways include:

Detection in biological fluids
Methamphetamine and amphetamine are often measured in urine or blood as part of a drug test for sports, employment, poisoning diagnostics, and forensics.
Uterine inversion is when the uterus turns inside out, usually following childbirth. Symptoms include postpartum bleeding, abdominal pain, a mass in the vagina, and low blood pressure. Rarely inversion may occur not in association with pregnancy.Risk factors include pulling on the umbilical cord or pushing on the top of the uterus before the placenta has detached. Other risk factors include uterine atony, placenta previa, and connective tissue disorders. Diagnosis is by seeing the inside of the uterus either in or coming out of the vagina.Treatment involves standard resuscitation together with replacing the uterus as rapidly as possible. If efforts at manual replacement are not successful surgery is required. After the uterus is replaced oxytocin and antibiotics are typically recommended. The placenta can then be removed if it is still attached.Uterine inversion occurs in about 1 in 2,000 to 1 in 10,000 deliveries. Rates are higher in the developing world. The risk of death of the mother is about 15% while historically it has been as high as 80%. The condition has been described since at least 300 BC by Hippocrates. Signs and symptoms
Uterine inversion is often associated with significant postpartum bleeding. Traditionally it was thought that it presented with haemodynamic shock "out of proportion" with blood loss, however blood loss has often been underestimated. The parasympathetic effect of traction on the uterine ligaments may cause bradycardia.