Clinical consequences of abrupt drug withdrawal

Sleep and delirium in ICU patients: a review of mechanisms and manifestations

Sleep deprivation and delirium are conditions commonly encountered in intensive care unit patients. Sleep in these patients is characterized by sleep fragmentation, an increase in light sleep, and a decrease of both slow wave sleep and rapid eye movement sleep. The most common types of delirium in this population are hypoactive and mixed-type. Knowledge about the mechanisms of sleep and delirium has evolved over time, but these phenomena are not yet well understood. What is known, however, is that different areas in the brainstem transmit information to the thalamus and cortex necessary for sleep-wake regulation. Delirium is related to an imbalance in the synthesis, release, and inactivation of some neurotransmitters, particularly acetylcholine and dopamine. The relationship between sleep deprivation and delirium has been studied for many years and has been viewed as reciprocal. The link between them may be ascribed to shared mechanisms. An imbalance in neurotransmitters as well as alteration of melatonin production may contribute to the pathogenesis of both phenomena. A better understanding of the mechanisms and factors that contribute to sleep deprivation and delirium can guide the development of new methods and models for prevention and treatment of these problems and consequently improve patient outcomes.

Steroid withdrawal syndrome after successful treatment of Cushing's syndrome: a reminder

Steroid withdrawal syndrome (SWS) usually refers to relapse of the disease being treated after withdrawal of glucocorticoid therapy, or the symptoms of adrenal insufficiency which occur when glucocorticoids are rapidly reduced or stopped. A less well-recognised form of SWS is that which develops when patients experience a symptom complex similar to that of adrenal insufficiency despite acceptable cortisol levels. We describe three patients who presented with this form of SWS following surgical treatment for endogenous Cushing's syndrome. All responded well to a short-term increase in the dose of glucocorticoid replacement therapy, with the median duration of the syndrome being 10 months (range 6-10 months). Trough serum cortisol levels above 100 nmol/l, with peaks between 460 and 750 nmol/l were documented in the first two patients at presentation with SWS. It is thought that the syndrome may result from development of tolerance to glucocorticoids, and mediators considered to be important in its development include interleukin-6, corticotrophin-releasing hormone, vasopressin, and central noradrenergic and dopaminergic systems. The exact underlying mechanism for SWS remains unclear. However, with increasing recommendations for use of lower doses of replacement glucocorticoids, its incidence may increase. Physicians need to be aware of this condition, which is self-limiting and easily treated by a temporary increase in the dose of glucocorticoid replacement therapy. It is possible that a slower glucocorticoid tapering regimen than that used in the standard postoperative management of patients undergoing pituitary surgery may reduce the risk of development of SWS.

Compliance with antidepressant therapy and antidepressant discontinuation symptoms

OBJECTIVE

Compliance with antidepressant medication is important in order to achieve all the goals of antidepressant therapy. These goals include symptom resolution, restoration of normal functioning and prevention of relapse or recurrent episodes.

METHOD

We discuss compliance and review adverse symptoms that may occur when antidepressant treatment is abruptly discontinued or interrupted.

RESULTS

The physician's role in managing compliance includes preventing or minimizing the risk for discontinuation symptoms, counselling patients regarding the risk for symptoms if doses are missed and choosing pharmacotherapy that is forgiving of non-compliance. Physicians also need to recognize the symptoms of discontinuation syndrome in order to differentiate patients who are non-compliant from patients who require a dosage adjustment or adjunctive therapy. Finally, physicians need to understand how to treat discontinuation symptoms when they do occur.

CONCLUSION

Since published data indicate that between 30% and 60% of patients do not take their medications as prescribed, non-adherence to antidepressant medication is likely to be a significant clinical issue in the management of many patients.

The role of recreational drugs in trauma

The association of trauma with illicit/recreational drugs is being increasingly recognized but is difficult to quantify. Significant amounts of these substances are readily available and may be taken alone, in combination with other drugs or with alcohol. The acute and chronic effects of these drugs result in numerous difficulties in management. Health-care workers involved in the treatment of trauma must have a high index of suspicion for the presence of drugs and a detailed knowledge of their effects. In this article we will review the scale of the problem, the common drugs abused and their effects, and we will discuss guidelines for management.

Substance abuse and withdrawal in the intensive care unit. Contemporary issues

Because 36% of intentional injury victims are drug dependent, the association between drug abuse and violence, especially in urban settings, is high. Withdrawal syndromes in ICU patients confuse their clinical management, may be extremely difficult to diagnose, are often lethal, need to be suspected, and should be prophylaxed against; therefore, all ICU patients should be considered to be at high risk for drug or alcohol dependence, should be tested for evidence of such drugs, and should be interviewed (together with their family members) for the presence of drug dependence traits. Appropriate patients should be referred for formal evaluation and treatment. Withdrawal syndromes must be promptly recognized, differentiated from traumatic or metabolic deterioration, and immediately treated. As patients are unique, so is their drug dependence. Individualized withdrawal therapy, not a "one method fits all" approach, works best. The mainstay of most withdrawal therapy is supportive care and benzodiazepine therapy. Also, considering the high rate of multiple intoxicants present in trauma patients, withdrawal can occur from multiple agents in a single patient, further compounding these difficulties. Withdrawal from unusual substances, such as GHB, or from therapeutic interventions (e.g., prolonged opioid or benzodiazepine administration) also must be considered.

Opioid and Benzodiazepine Withdrawal Syndrome in Adult Burn Patients

The prolonged use of continuous intravenous sedation [benzodiazepines (BZDs)] and pain medication [opioids (OPs)] is now common in intensive care units. Few studies have evaluated the characteristics that may lead to an acute withdrawal syndrome when these long-term medications are withdrawn. Those studies that have made recommendations for weaning rates to prevent withdrawal have given these recommendations with minimal data to support their recommendations. The purpose of this study was to retrospectively review the records of adult burn patients for the presence of acute BZD or OP withdrawal syndrome and to characterize whether patterns of BZD or OP administration or weaning rates contribute to the development of acute withdrawal syndrome. We found no relation of acute withdrawal syndrome to peak dose, total dose, or duration of dose of BZD/OP before the terminal withdrawal phase. There was a significant relationship between the rate of BZD/OP weaning in the terminal drug withdrawal phase and the percentage of days that patients experienced withdrawal symptoms ( P < 0.005). Those patients who underwent a prolonged terminal weaning from these medications experienced fewer symptoms. The optimal rate of weaning that would allow decreased ventilator and intensive care unit length of stay without development of acute withdrawal symptoms is yet to be determined.

Nefazodone in community use: the results of prescription-event monitoring

PURPOSE

This study was a pharmacovigilance exercise which aimed to determine the post-marketing event profile of nefazodone, a newly marketed antidepressant, in community use.

METHODS

Information was collected on patients included in a non-interventional observational cohort study conducted by means of Prescription-Event Monitoring in England. Incidence densities were calculated for all reported events.

RESULTS

Information was obtained for 11 834 patients. Nausea and dizziness were the most frequent adverse events that led to stopping nefazodone and the most frequently reported events during the first month of treatment. Unsteadiness and falls were reported more frequently in the elderly. Hepatic events, involuntary movements, thrombocytopenia, hallucinations and withdrawal reactions were reported rarely but were possibly associated with nefazodone. Eight overdoses involving nefazodone alone were reported with no serious clinical sequelae. Two premature births, one low birth weight term baby and two babies with renal abnormalities were outcomes in 38 pregnancies exposed in the first trimester to nefazodone. One death in a woman aged 71 years followed an illness with serotonergic features.

CONCLUSIONS

Event data are presented for patients dispensed nefazodone in the community. The findings are discussed.

Acute withdrawal syndrome related to the administration of analgesic and sedative medications in adult intensive care unit patients

OBJECTIVES

To estimate the frequency of acute withdrawal syndrome related to the administration of analgesic and sedative medications in mechanically ventilated adult intensive care unit (ICU) patients; to identify associated clinical factors.

DESIGN

Retrospective review of medical records.

SETTING

An adult trauma/surgical ICU in an urban Level I trauma center.

PATIENTS

Twenty-eight mechanically ventilated adult trauma/ surgical ICU patients requiring >7 days of ICU care.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Daily doses of all opioid, sedative, hypnotic, and major tranquilizer drugs administered to each patient were measured, as was duration of ICU stay, duration of mechanical ventilation, and duration of the administration of analgesic, sedative, and neuromuscular blocking agents (NMBAs) for each patient. All opioids and benzodiazepines were converted to their respective fentanyl and lorazepam equivalent units based on potency and bioavailability. Calculation of the weaning rate for each patient during tapering from opioid and benzodiazepine medications was performed. The presence or absence of acute withdrawal syndrome was identified for each patient. Nine (32.1%) patients developed acute withdrawal syndrome potentially related to the administration of analgesic or sedative medications. Patients in the withdrawal group received significantly higher mean daily (p = .049) and peak (p = .032) doses of fentanyl equivalents, as well as higher mean daily lorazepam equivalents (p = .049) compared with patients not experiencing withdrawal. Patients in the withdrawal group were also significantly more likely to have received neuromuscular blocking agents (p = .004) or propofol (p =.026) for >1 day during ICU admission compared with patients not experiencing withdrawal. Duration of mechanical ventilation (p = .049), benzodiazepine therapy (p = .048), and propofol therapy (p = .049) was also significantly longer in the group experiencing withdrawal. Withdrawal patients received a significantly lower mean daily dose of haloperidol (p = .026). There was a significant association between the development of withdrawal syndrome and the presence of ARDS (p = .017). Finally, the slopes of the lines representing opioid and benzodiazepine drug weaning were more steep for the withdrawal group, although these results did not achieve statistical significance.

CONCLUSIONS

These results suggest that mechanically ventilated adult patients with extended ICU care (> or =7 days) who receive large doses of analgesic and sedative medications are at risk for acute withdrawal syndromes during drug weaning. The association between ARDS and withdrawal syndrome, combined with the observation that withdrawal syndromes were also associated with the use of neuromuscular blocking agents and prolonged mechanical ventilation, suggests that patients with ARDS may be more likely to receive high doses of analgesic and sedative medications, and are therefore at increased risk for withdrawal syndrome.

Nicotine withdrawal versus other drug withdrawal syndromes: similarities and dissimilarities

Many of the symptoms of nicotine withdrawal are similar to those of other drug withdrawal syndromes: anxiety, awakening during sleep, depression, difficulty concentrating, impatience, irritability/anger and restlessness. Slowing of the heart rate and weight gain are distinguishing features of tobacco withdrawal. Although nicotine withdrawal may not produce medical consequences, it lasts for several weeks and can be severe in some smokers. Like most other drug withdrawals, nicotine withdrawal is time-limited, occurs in non-humans, is influenced by instructions/expectancy and abates with replacement therapy and gradual reduction. Unlike some other drug withdrawal syndromes, protracted, neonatal or precipitated withdrawal does not occur. Whether nicotine withdrawal is associated with tolerance, acute physical dependence, greater duration and intensity of use, rapid reinstatement, symptom stages, cross-dependence with other nicotine ligands, reduction by non-pharmacological interventions and genetic influences is unclear. Whether nicotine withdrawal plays a major role in relapse to smoking has not been established but this is also true for other drug withdrawal syndromes.

Benzodiazepine poisoning. Clinical and pharmacological considerations and treatment

Benzodiazepines are among the most frequently prescribed drugs worldwide. This popularity is based not only on their efficacy but also on their remarkable safety. Pure benzodiazepine overdoses usually induce a mild to moderate central nervous system depression; deep coma requiring assisted ventilation is rare, and should prompt a search for other toxic substances. The severity of the CNS depression is influenced by the dose, the age of the patient and his or her clinical status prior to the ingestion, and the coingestion of other CNS depressants. In severe overdoses, benzodiazepines can occasionally induce cardiovascular and pulmonary toxicity, but deaths resulting from pure benzodiazepine overdoses are rare. Quantitative determinations of benzodiazepines are not useful in the clinical management of intoxicated patients since there is no correlation between serum concentrations and pharmacological and toxicological effects. Benzodiazepine overdoses occurring during pregnancy rarely induce serious morbidity in mothers or fetuses, although large doses administered near delivery can induce respiratory depression in neonates. The teratogenic potential of benzodiazepines remains controversial, but is probably small if it exists at all. There is clear evidence that the prolonged use of even therapeutic doses of benzodiazepines will lead to dependence. The risk of developing significant withdrawal symptoms is related to dosage and duration of treatment. Prevention of gastrointestinal absorption should be initiated in all intentional benzodiazepine overdoses. Forced diuresis and dialysis techniques are not indicated since they will not significantly accelerate the elimination of these agents. Intravenous administration of flumazenil, a pure benzodiazepine antagonist, effectively reverses benzodiazepine-induced CNS depression.