Poison may be removed from the GI tract using several decontamination procedures. Antidotes are used to inhibit enzymes that mediate the formation of toxic drug metabolites. Alternatively, the metabolites are detoxified by endogenous cosubstrates. The concentration of the cosubstrate is maintained to prevent it from interacting with cell macromolecules and causing cell death. Lipid-insoluble, ionized drugs are primarily excreted through the renal route. Lipid-soluble, nonionized forms undergo tubular reabsorption, which increases their concentration in the blood. Diuretics may inhibit reabsorption by decreasing the drug's concentration gradient and increasing flow through the tubule. Alternatively, altering tubular urine's pH increases the excretion of ionized drugs. Acidic drugs like phenobarbital, for instance, are eliminated faster in alkaline urine, where the drug is largely ionized. On the contrary, basic drugs like amphetamines are largely ionized through urine acidification, which enhances their elimination from the body. Hemodialysis is another enhanced drug elimination method to correct fluid and electrolyte imbalance and remove toxic metabolites.