Copper deficiency, or hypocupremia,  is defined either as insufficient copper to meet the needs of the body, or as a serum copper level below the normal range. Symptoms may include fatigue, decreased red blood cells, early greying of the hair, and neurological problems presenting as numbness, tingling, muscle weakness, and ataxia. The neurodegenerative syndrome of copper deficiency has been recognized for some time in ruminant animals, in which it is commonly known as "swayback". Copper deficiency can manifest in parallel with vitamin B12 and other nutritional deficiencies. Overview
The most common cause of copper deficiency is a remote gastrointestinal surgery, such as gastric bypass surgery, due to malabsorption of copper, or zinc toxicity. On the other hand, Menkes disease is a genetic disorder of copper deficiency involving a wide variety of symptoms that is often fatal.Copper is required for the functioning of many enzymes, such as cytochrome c oxidase, which is complex IV in the mitochondrial electron transport chain, ceruloplasmin, Cu/Zn superoxide dismutase, and in amine oxidases. These enzyme catalyze reactions for oxidative phosphorylation, iron transportation, antioxidant and free radical scavenging and neutralization, and neurotransmitter synthesis, respectively. Diets vary in the amount of copper they contain, but may provide about 5 mg/day, of which only 20-50% is absorbed. The diet of the elderly may have a lower copper content than the recommended daily intake.
Side effects
After an intake of 1.5 mg levonorgestrel in clinical trials, very common side effects (reported by 10% or more) included: hives, dizziness, hair loss, headache, nausea, abdominal pain, uterine pain, delayed menstruation, heavy menstruation, uterine bleeding, and fatigue; common side effects (reported by 1% to 10%) included diarrhea, vomiting, and painful menstruation; these side effects usually disappeared within 48 hours. However, the long term side effects common with oral contraceptives such as arterial disease are lower with levonorgestrel than in combination pills.Levonorgestrel as a contraceptive intrauterine device is associated with a higher risk of breast cancer than with non-use. Overdose
Overdose of levonorgestrel as an emergency contraceptive has not been described. Nausea and vomiting might be expected. Interactions
If taken together with drugs that induce the CYP3A4 cytochrome P450 liver enzyme, levonorgestrel may be metabolized faster and may have lower effectiveness. These include, but are not limited to barbiturates, bosentan, carbamazepine, felbamate, griseofulvin, oxcarbazepine, phenytoin, rifampin, St. Johns wort and topiramate. Pharmacology
Pharmacodynamics
Levonorgestrel is a progestogen with weak androgenic activity. It has no other important hormonal activity, including no estrogenic, glucocorticoid, or antimineralocorticoid activity. The lack of significant mineralocorticoid or antimineralocorticoid activity with levonorgestrel is in spite of it having relatively high affinity for the mineralocorticoid receptor, which is as much as 75% of that of aldosterone. Progestogenic activity
Levonorgestrel is a progestogen; that is, an agonist of the progesterone receptor (PR), the main biological target of the progestogen sex hormone progesterone. It has effects similar to those of the hormone progesterone.