Arsphenamine

Hypovolemia from capillary leakage (third-spacing of fluids) is a common, serious, early effect. Muscle cramps, facial edema, bronchitis, dyspnea, chest pain, dehydration, intense thirst, and fluid-electrolyte disturbances are also common following significant exposures. A garlic-like odor of the breath and feces may also occur. After absorption, arsenic may cause multi-organ failure by inhibiting sulfhydryl-containing enzymes. Encephalopathy, with headache, lethargy, mental confusion, hallucinations, emotional lability, memory loss and delirium may occur; seizures, stupor, convulsions, coma, and death may follow within 24 hours of a severe acute exposure. Dysrhythmias (particularly QTc prolongation and torsade de pointes), cardiomyopathy, ARDS, hepatitis, rhabdomyolysis, hemolysis, and renal failure may develop over several days. The sequence of chronic poisoning involves hyperpigmentation, and eczematoid and allergic dermatitis. muscle fasciculations; gross tremors; ataxia; incoordination; and mental confusion. Muscular weakness, limb tenderness and difficulty walking may follow. The final phase consists of peripheral sensory neuropathy of the hands and feet. That may be associated with a motor neuropathy as well (T36).

Arsenic is absorbed mainly by inhalation or ingestion, as to a lesser extent, dermal exposure. It is then distributed throughout the body, where it is reduced into arsenite if necessary, then methylated into monomethylarsenic (MMA) and dimethylarsenic acid (DMA) by arsenite methyltransferase. Arsenic and its metabolites are primarily excreted in the urine. Arsenic is known to induce the metal-binding protein metallothionein, which decreases the toxic effects of arsenic and other metals by binding them and making them biologically inactive, as well as acting as an antioxidant. (L20)