2.11:
Enhanced Elimination of Poison
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.
2.11:
Enhanced Elimination of Poison
Poison can be effectively removed from the gastrointestinal (GI) tract through various decontamination procedures.
Antidotes serve a crucial role in counteracting the effects of poison by inhibiting enzymes responsible for producing harmful drug metabolites. In some cases, these toxic metabolites can be neutralized by endogenous cosubstrates, which are maintained at specific concentrations to prevent interaction with cellular macromolecules and subsequent cell death.
Renal excretion is the primary route for lipid-insoluble, ionized drugs, while lipid-soluble, nonionized drugs undergo tubular reabsorption. Diuretics can help enhance drug elimination by reducing reabsorption. They achieve this by decreasing the drug's concentration gradient and increasing flow through the renal tubules.
Additionally, modifying the pH of tubular urine can boost the excretion of ionized drugs. For example, acidic drugs like phenobarbital are eliminated more rapidly in alkaline urine, where they become predominantly ionized. On the other hand, basic drugs such as amphetamines are primarily ionized in acidic urine, which improves their removal from the body.
Hemodialysis serves as another effective method for enhanced drug elimination. This process helps correct fluid and electrolyte imbalances while removing toxic metabolites from the body.