Chapter 114: Strychnine

INTRODUCTION

HISTORY AND EPIDEMIOLOGY

Strychnine alkaloid occurs naturally in Strychnos nux-vomica, a tree native to tropical Asia and North Australia, and in Strychnos ignatii and Strychnos tiente, trees native to South Asia. The alkaloid was first isolated in 1818 by Pelletier and Caventou.^5,15 It is an odorless and colorless crystalline powder that has a bitter taste when dissolved in water. In addition to strychnine, the dried seeds of S. nux-vomica contain brucine, a structurally similar, although less potent, alkaloid.⁸⁷ Strychnine is available from commercial sources in its salt form, usually as nitrate, sulfate, or phosphate.

Strychnine was first introduced as a rodenticide in 1540, and in subsequent centuries was used medically as a cardiac, respiratory, and digestive stimulant,⁴⁴ as an analeptic,⁹⁰ and as an antidote to barbiturate⁸⁹ and opioid overdoses.⁵⁹ Nonketotic hyperglycemia,^9,80 sleep apnea,⁷⁶ and snake bites¹⁵ were also once considered indications for strychnine use. In 1982, at least 172 commercial products were found to contain strychnine, including 77 rodenticides, 25 veterinary products, and 41 products made for human use.⁸³ In subsequent years, the use of strychnine significantly decreased; some countries such as the European Union banned its use as a rodenticide in 2006, and most of its prior medicinal indications are no longer utilized. Currently, strychnine is only widely used for moles, gophers, and pigeons and as a research tool for the study of glycine receptors. Most commercially available strychnine-containing products contain about 0.25% to 0.5% strychnine by weight.⁸³

Between 1926 and 1928, strychnine killed more than 3 Americans every week.^5,27 In 1932, it was the most common cause of lethal poisoning in children,^5,83 and one-third of the unintentional poison-related deaths in children younger than 5 years were attributed to strychnine.⁶⁰ Currently, strychnine poisoning is rare and continues to decrease in the United States, although deaths are still reported. The Toxic Exposure Surveillance System (TESS) and National Poison Data System (NPDS) data of the American Association of Poison Control Centers (AAPCC) reported 1163 strychnine exposures including 5 deaths during the 10 years from 2006 to 2015 (Chap. 130).

In the modern era, strychnine poisoning typically results from deliberate exposure with suicidal and homicidal intent,^27,48 as well as from unintentional poisoning by a Chinese herbal medicine (Maqianzi)¹⁶ and a Cambodian traditional remedy (slang nut).^46,48,51 Maqianzi is used to treat limb paralysis, severe rheumatism, inflammatory disease, and skeletal fluorosis⁵⁰ whereas slang nut is used to treat gastrointestinal diseases. The bitter taste of strychnine has led to its use as an adulterant in heroin⁴² and cocaine.^13,22,64 There are also reports of strychnine poisoning from adulterated amphetamines,²² 3,4-methylenedioxymethamphetamine (MDMA),²⁵ Spanish fly,¹² and from ...