Chronic aspirin toxicity (salicylism) may develop in persons who take 3 gm or more daily (the dose used to treat chronic inflammatory conditions). Chronic salicylism is manifested by headache, dizziness, ringing in the ears (tinnitus), difficulty in hearing, mental confusion, drowsiness, nausea, vomiting, and diarrhea. The CNS changes may progress to convulsions and coma. The morphologic consequences of chronic salicylism are varied. Most often, there is an acute erosive gastritis (Chapter 15), which may produce overt or covert GI bleeding and lead to gastric ulceration. A bleeding tendency may appear concurrently with chronic toxicity because aspirin irreversibly inhibits platelet cyclooxygenase and blocks the ability to make thromboxane A2, an activator of platelet aggregation (Chapter 4). Petechial hemorrhages may appear in the skin and internal viscera, and bleeding from gastric ulcerations may be exaggerated.
Proprietary analgesic mixtures of aspirin and phenacetin or its active metabolite, acetaminophen, when taken throughout several years, can cause tubulointerstitial http://ebooksmedicine.net
Table 8.6 Common Drugs of Abuse
OpioidnarcoticsMuopioidreceptor(agonist)Heroin,hydromorphone(Dilaudid)OxycodoneMethadone(Dolophine)
Phencyclidine-likedrugsNMDAglutamatereceptorchannel(antagonist)Phencyclidine(PCP)(i.e.,“angeldust”)Ketamine
CB1, Cannabinoidreceptortype1;GABA, γ-aminobutyricacid;5-HT2, 5-hydroxytryptamine;NMDA, N-methyl-D-aspartate;PCP, 1-(1-phenylcyclohexyl)piperidine.DatafromHymanSE:A28-year-oldmanaddictedtococaine,JAMA 286:2586,2001.
nephritis with renal papillary necrosis. This clinical entity is referred to as analgesic nephropathy (Chapter 14).
Drug abuse generally involves the use of mind-altering substances beyond therapeutic or social norms. Drug addiction and overdose are serious public health problems. Common drugs of abuse are listed in
Table 8.6 . Considered here are cocaine, opiates, and marijuana, with a brief mention of a few other drugs.
In 2014, it was estimated that there were 1.5 million users of cocaine in the United States, of which approximately 15% to 20% were users of “crack” cocaine. Use is highest among adults 18 to 25 years of age, of whom 1.4% reported taking cocaine within the past month. Extracted from the leaves of the coca plant, cocaine usually is prepared as a water-soluble powder, cocaine hydrochloride, but when sold on the street it is liberally diluted with talcum powder, lactose, or other look-alikes. Crystallization of the pure alkaloid from cocaine hydrochloride yields nuggets of crack (so called because of the popping sound it makes when heated). The pharmacologic actions of cocaine and crack are identical, but crack is far more potent. Both forms can be snorted, smoked after mixing with tobacco, ingested, or injected subcutaneously or intravenously.