Variation in human plasma cholinesterase activity during low-dose cocaine administration

Maternal Exposure and Neonatal Effects of Drugs of Abuse

The public health crisis of pregnant women being exposed to drugs of abuse and of its impact on their unborn children continues to grow at an alarming rate globally. The state of pregnancy is unique, with physiological changes that can lead to changes in the way drugs are handled by the body in both pharmacokinetics and response. These changes place the pregnant woman, fetus, and newborn infant at risk, as many of these drugs can cross the placenta and into breast milk. The substances most commonly linked to harmful effects include alcohol, tobacco, cannabis, stimulants, and opioids. The pharmacological and toxicological changes caused by in utero exposure or breastfeeding exposure are difficult to study, and the full extent of the mechanisms involved are not fully understood. However, these changes can significantly affect the risks of substance abuse and influence optimal treatment of pregnant women with a substance use disorder. In addition, newborns who were exposed to drugs of abuse in utero can experience withdrawal syndromes. Pharmacological management in infants is used to guide and treat withdrawal symptoms, with the goal being to improve the infant's sleep, eating, and comfort. Several barriers may prevent pregnant women from seeking help for substance use, including stigma and interactions with the legal system. Understanding changes in pharmacology, including pharmacokinetic changes that happen during pregnancy, is essential for anticipating the extent of maternal exposure and neonatal adverse effects.

Drugs of abuse: management of intoxication and antidotes

Illicit drug intoxications are an increasing public health problem for which, in most cases, no antidotes are clinically available. The diagnosis and treatment of these intoxications requires a trained clinician with experience in recognizing the specific signs and symptoms of intoxications to individual drugs as well as polydrug intoxications, which are more the rule than the exception. To make the diagnosis, the clinical observation and a urine toxicology test are often enough. Evaluating the blood levels of drugs is frequently not practical because the tests can be expensive and results may be delayed and unavailable to guide the establishment of a treatment plan. Other laboratory tests may be useful depending on the drug or drugs ingested and the presence of other medical complications. The treatment should be provided in a quiet, safe and reassuring environment. Vital signs should be closely monitored. Changes in blood pressure, respiratory frequency and temperature should be promptly treated, particularly respiratory depression (in cases of opiate intoxication) or hyperthermia (in cases of cocaine or amphetamine intoxication). Intravenous fluids should be administered as soon as possible. Other psychiatric and medical complication should receive appropriate symptomatic treatment. Research on immunotherapies, including vaccines, monoclonal and catalytic antibodies, seems to be a promising approach that may yield specific antidotes for drugs of abuse, helping to ameliorate the morbidity and mortality associated with illicit drug intoxications.

Mechanisms of acute cocaine toxicity

Patients with acute cocaine poisoning present with life-threatening symptoms involving several organ systems. While the effects of cocaine are myriad, they are the result of a limited number of cocaine-protein interactions, including monoamine transporters, neurotransmitter receptors and voltage-gated ion channels. These primary interactions trigger a cascade of events that ultimately produce the clinical effects. The purpose of this article is to review the primary interactions of cocaine and the effects that these interactions trigger. We also describe the progression of symptoms observed in cocaine poisoning as they relate to serum cocaine concentrations.

Heart rate variability by triangular index in infants exposed prenatally to cocaine

BACKGROUND

In adults, heart rate variability triangular index (HRVi) is a highly reproducible measure of heart rate variability (HRV), which makes it more suitable for use in longitudinal studies. Although normative data have been published for newborns, studies in infants with pathological conditions are lacking.

METHODS

From 1997 to 2000, within the first 4 days of life, we prospectively evaluated HRVi in cocaine-exposed asymptomatic newborns (N = 97) by Holter monitoring. Their data were compared with infants from two control groups (one with no in utero drug exposure, N = 102; the other with exposure to alcohol, nicotine, or marijuana but no cocaine, N = 111).

RESULTS

In assessing concordance between and within operators for HRVi, the intraclass correlations were 0.983 (95% CI: 0.958, 0.994) and 0.997 (95% CI: 0.984, 0.999), respectively. Infants with in utero cocaine exposure had significantly (P < 0.0001) lower HRVi than those exposed to other drugs and to no drugs in utero. If abnormal HRVi is defined as < fifth percentile for the no drug exposed group (HRVi < 8), 10% of the cocaine-exposed newborns, in contrast to 2% in each of the control groups (P = 0.003) had abnormal values.

CONCLUSION

HRVi is a reliable measure to study heart rate variability in newborns. Asymptomatic infants with in utero cocaine exposure have lower HRVi. Our study supports the clinical use of an abnormal HRVi as a value < 8 for newborn infants.

Cardiac and hemodynamic assessment of patients with cocaine-associated chest pain syndromes

BACKGROUND

Animal and human experimental studies have yielded conflicted data regarding the effects of cocaine on cardiovascular function. We studied the cardiac and hemodynamic profiles in emergency department chest pain patients following recent cocaine use.

METHODS

After obtaining informed consent, emergency department patients who presented with a chief complaint of chest pain and cocaine use within 24 hours of arrival were prospectively enrolled. All patients underwent a structured 40-item history and physical examination and were placed on the IQ Noninvasive Hemodynamic Surveillance System (Renaissance Technology, Inc., Newton, PA), a validated transthoracic cardiac output monitor. The principal measurements obtained included cardiac output, cardiac index, and stroke volume. Data were analyzed with standard descriptive techniques.

RESULTS

Twenty-seven patients were enrolled (median age, 37 years [range, 23-54]; 74% male). Patients used a mean of $200 worth of cocaine, usually crack (67%). Patients had a history of tobacco use (82%), prior myocardial infarction (33%), and prior cocaine-associated chest pain (67%). The median (interquartile range; IQR) for the hemodynamic parameters were: mean arterial blood pressure 92 mm Hg (IQR 85-100); heart rate 83/min (IQR 72-98); cardiac output 6.9 L/min (IQR 5.1-7.2); cardiac index 3.2 L/min/m2 (IQR 2.4-4.0); stroke volume 78 mL/beat (IQR 64-93).

CONCLUSION

Most emergency department patients with cocaine-associated chest pain have normal cardiac profiles at the time of presentation. The negative inotropic effects of high doses of cocaine observed in animal models do not appear to be present in patients who develop chest pain after using recreational doses of cocaine.

The effects of nutrition on plasma cholinesterase activity and cocaine toxicity in mice

BACKGROUND

Low plasma cholinesterase activity is associated with severe cocaine toxicity in human subjects and animal experiments. Exogenously enhanced plasma cholinesterase activity is protective against cocaine toxicity in animals. Cocaine users tend to have lower plasma cholinesterase activity than controls. Yet, when cocaine users are allowed to use cocaine in controlled settings without dietary restriction, their plasma cholinesterase activity increases. This study evaluates the influence of diet on plasma cholinesterase activity and cocaine toxicity.

METHODS

Forty-five Swiss albino mice were maintained on a high (30%) protein diet for 3 weeks. They were then randomized into equal groups and given either the high protein diet, an isocaloric low protein diet, or a protein and calorie deficient diet which consisted of reduced intake of the high protein diet. Body weights and plasma cholinesterase activities were measured after a 21-day study period. All animals then received a fixed dose of intraperitoneal cocaine and were observed for seizures and death.

RESULTS

Body weights and plasma cholinesterase activities of the high protein animals remained stable. Weights for the low protein and reduced intake animals fell by 5% and 15%, respectively (p < 0.05 for both vs baseline). Similarly, plasma cholinesterase activities for the low protein and reduced intake animals fell by 4% and 10%, respectively (p = 0.06 for low protein and < 0.05 for reduced intake vs baseline). Cocaine caused seizures in 67% of the high protein animals as compared to 93% and 100% of the low protein and reduced intake animals, respectively (p < 0.05 for high protein vs reduced intake). None of the high protein animals died as compared to 20% and 100% of the low protein and reduced intake animals, respectively (p < 0.05 for high protein vs reduced intake).

CONCLUSION

Protein and calorie malnutrition is associated with a reduction in plasma cholinesterase activity and enhanced cocaine toxicity in mice. Further study is needed to determine if dietary factors are partially responsible for variations in plasma cholinesterase activity and cocaine susceptibility in humans.