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Subsumed under this title is a diverse group of disorders of the nervous system that result from alcohol, drugs, and other injurious or poisonous substances. The neurologist must be concerned with the myriad of chemical agents that may adversely affect the nervous system; they abound in the environment as household products, insecticides, industrial solvents, and other poisons, as well as substances that may have therapeutic value but are used for their “recreational” psychotropic effects, or are conventional medications with known toxic effects. Also among the neurotoxins are those generated by bacteria and other infectious organisms, as well as toxins found in nature, such as marine toxins. Together, the effect of these agents and toxins on the nervous system constitutes the field of neurotoxicology.
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It would hardly be possible within one chapter to discuss the innumerable drugs and toxins that affect the nervous system. The interested reader is referred to a number of comprehensive monographs and references such as Casarett and Doull’s Toxicology, edited by Klaassen and Occupational Neurology edited by Lotti and Bleecker. In addition, a current handbook of pharmacology and toxicology is a useful part of the library of every physician. The scope of this chapter is also limited because the therapeutic and adverse effects of many drugs are considered elsewhere in this volume in relation to particular symptoms and diseases. Thus, the adverse effects of antibiotics on cochlear and vestibular function and on neuromuscular transmission are discussed in Chaps. 14 and 46, respectively. Many of the undesirable side effects of the common drugs used in the treatment of extrapyramidal motor symptoms, pain, headache, seizure, sleep disorders, psychiatric illnesses, and so forth are also considered in the chapters dealing with each of these disorders and in the chapters that cover psychiatric diseases. Cyanide and carbon monoxide poisoning are discussed in relation to anoxic encephalopathy (see Chap. 39). A number of therapeutic agents that predictably damage the peripheral nerves (e.g., cisplatin, disulfiram, vincristine) are mentioned in this chapter but are discussed further in Chap. 43, and those that affect muscle are included in Chap. 45.
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The presentation of this subject is introduced by some general remarks on the action of drugs on the nervous system and is followed by discussion of the main classes of agents that affect nervous function:
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Alcohol and alcoholism
Opiates and synthetic analgesic drugs
Sedative-hypnotic drugs
Antipsychosis drugs
Antidepressant drugs
Stimulants
Psychoactive drugs and hallucinogens
Bacterial toxins
Plant poisons venoms, bites, and stings
Heavy metals and industrial toxins
Antineoplastic and immunosuppressive agents
Antibiotics
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GENERAL PRINCIPLES OF NEUROTOXICOLOGY
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The rational use of any drug requires knowledge of the best route of administration, the drug’s absorption characteristics, its distribution in the nervous system and other organs, and its biotransformations and excretion (pharmacokinetics). Because every drug, if given in excess, has some adverse effects, therapeutics and ...