Phencyclidine excretion

Khajawall, A.M., and Simpson, G.M. Peculiarities of phencyclidine urinary excretion and monitoring. J. Toxicol Clin Toxicol 19(8) 835-842, 1982-83. 

The answer is a. (Hardman, pp 16-20.) Sodium bicarbonate is excreted principally in the urine and alkalinizes it. Increasing urinary pH interferes with the passive renal tubular reabsorption of organic acids (such as aspirin and phenobarbital) by increasing the ionic form of the drug in the tubular filtrate. This would increase their excretion. Excretion of organic bases (such as amphetamine, cocaine, phencyclidine, and morphine) would be enhanced by acidifying the urine. 

Both acid and alkaline manipulation of urine applies the principle of ion-trapping in the renal tubules. However, acid diuresis is not advocated because of the risk of developing myoglobinuria and acute renal failure. The intent of modifying the urine pH toward an acidic side is to promote the excretion of drugs with an alkaline pKa such as phencyclidine or amphetamine. 

Two recent reviews 22 contain considerable information on the absorption, distribution, metabolism, and excretion of phencyclidine. 

Avoiding restraints, intravascular volume repletion and perhaps muscle paralyzing drugs have been advocated. Although urinary acidification has been recommended to promote phencyclidine excretion, this... 

D. Enhancement of Elimination Enhancement of elimination is possible for a number of toxins, including manipulation of urine pH to accelerate renal excretion of weak acids and bases. For example, alkaline diuresis is effective in toxicity due to fluoride, isoniazid, fluoroquinolones, phenobarbital, and salicylates. Urinary acidiflcation may be useful in toxicity due to weak bases, including amphetamines, nicotine, and phencyclidine, but care must be taken to avoid acidosis and renal failure in rhabdomyolysis. Hemodialysis or hemoperfusion enhances the elimination of many toxic compounds, including acetaminophen, ethylene glycol, formaldehyde, lithium, methanol, procainamide, quinidine, salicylates, and theophylline. Cathartics such as sorbitol (70%) may decrease absorption and hasten removal of toxins from the gastrointestinal tract. 

Phencyclidine (PCP) is rapidly metabolized in the body and excreted in the urine as several hydroxy metabolites and the parent drug. Many gas chromatographic methods have been developed for screening of different drugs, such as that shown... 

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