Benzodiazepine withdrawal syndrome

Withdrawal symptoms occur during dose reduction and may include insomnia, anxiety, distress, weight loss, dizziness, night sweats, shaking, muscle twitches, aphasia, panic attacks, depression, numbness, dissociation, paranoia, indigestion, diarrhea, and photophobia. As withdrawal progresses, patients often find their physical and mental health improves with improved mood and improved cognition. A more complete list of possible symptoms stated in publications: Rapid discontinuation may result in a more serious syndrome ==Mechanism==

The neuroadaptive processes involved in tolerance, dependence, and withdrawal mechanisms implicate both the GABAergic and the glutamatergic systems. Gamma-Aminobutyric acid (GABA) is the major inhibitory neurotransmitter of the central nervous system; roughly one-quarter to one-third of synapses use GABA. GABA mediates the influx of chloride ions through ligand-gated chloride channels called GABAA receptors. When chloride enters the nerve cell, the cell membrane potential hyperpolarizes thereby inhibiting depolarization, or reduction in the firing rate of the post-synaptic nerve cell. Benzodiazepines potentiate the action of GABA, by binding a site between the α and γ subunits of the 5-subunit receptor thereby increasing the frequency of the GABA-gated chloride channel opening in the presence of GABA. When potentiation is sustained by long-term use, neuroadaptations occur which result in decreased GABAergic response. What is certain is that surface GABAA receptor protein levels are altered in response to benzodiazepine exposure, as is receptor turnover rate. The exact reason for the reduced responsiveness has not been elucidated but down-regulation of the number of receptors has only been observed at some receptor locations including in the pars reticulata of the substantia nigra; down-regulation of the number of receptors or internalization does not appear to be the main mechanism at other locations. Evidence exists for other hypotheses including changes in the receptor conformation, changes in turnover, recycling, or production rates, degree of phosphorylation and receptor gene expression, subunit composition, decreased coupling mechanisms between the GABA and benzodiazepine site, decrease in GABA production, and compensatory increased glutamatergic activity. Glutamate is the most abundant excitatory neurotransmitter in the vertebrate nervous system. Increased glutamate excitatory activity during withdrawal may lead to sensitization or kindling of the CNS, possibly leading to worsening cognition and symptomatology and making each subsequent withdrawal period worse. Those who have a prior history of withdrawing from benzodiazepines are found to be less likely to succeed the next time around. ==Diagnosis==

In severe cases, the withdrawal reaction or protracted withdrawal may exacerbate or resemble serious psychiatric and medical conditions, such as mania, schizophrenia, agitated depression, panic disorder, generalised anxiety disorder, and complex partial seizures and, especially at high doses, seizure disorders. ==Prevention==

According to the British National Formulary, it is better to withdraw too slowly rather than too quickly from benzodiazepines. ==Management==

, 5 mg capsules, are sometimes used as an alternative to diazepam for benzodiazepine withdrawal. Like diazepam, it has a long elimination half-life and long-acting active metabolites. Management of benzodiazepine dependence involves considering the person's age, comorbidity and the pharmacological pathways of benzodiazepines. Psychological interventions may provide a small but significant additional benefit over gradual dose reduction alone at post-cessation and at follow-up. With sufficient motivation and the proper approach, almost anyone can successfully withdraw from benzodiazepines. However, a prolonged and severe withdrawal syndrome can cause profound disability, which may lead to breakdown of relationships, loss of employment, financial difficulties, as well as more serious adverse effects such as hospitalization and suicide. As such, long-term users should not be forced to discontinue against their will. Medications While some substitutive pharmacotherapies may have promise, current evidence is insufficient to support their use. Some studies found that the abrupt substitution of substitutive pharmacotherapy was actually less effective than gradual dose reduction alone, and only three studies found benefits of adding melatonin, paroxetine, trazodone, in conjunction with a gradual dose reduction. Antipsychotics should be avoided during benzodiazepine withdrawal as they tend to aggravate withdrawal symptoms, including convulsions. Some antipsychotic agents may be riskier than others during withdrawal, especially clozapine, olanzapine or low potency phenothiazines (e.g., chlorpromazine), as they lower the seizure threshold and can worsen withdrawal effects; if used, extreme caution is required. • Barbiturates are cross tolerant to benzodiazepines and should generally be avoided; however phenobarbital can be used, as it is relatively safe, see below. • Benzodiazepines or cross tolerant drugs should be avoided after discontinuation, even occasionally. These include the nonbenzodiazepines Z-drugs, which have a similar mechanism of action. This is because tolerance to benzodiazepines has been demonstrated to be still present at four months to two years after withdrawal depending on personal biochemistry. Re-exposures to benzodiazepines typically resulted in a reactivation of the tolerance and benzodiazepine withdrawal syndrome. • Bupropion, which is used primarily as an antidepressant and smoking cessation aid, is contraindicated in people experiencing abrupt withdrawal from benzodiazepines or other sedative-hypnotics (e.g. alcohol), due to an increased risk of seizures. • Buspirone augmentation was not found to increase the discontinuation success rate. • Caffeine may worsen withdrawal symptoms because of its stimulatory properties. • Carbamazepine, an anticonvulsant, appears to have some beneficial effects in the treatment and management of benzodiazepine withdrawal; however, research is limited and thus the ability of experts to make recommendations on its use for benzodiazepine withdrawal is not possible at present. • Flumazenil has been found to stimulate the reversal of tolerance and the normalization of receptor function. However, further research is needed in the form of randomised trials to demonstrate its role in the treatment of benzodiazepine withdrawal. Flumazenil stimulates the up-regulation and reverses the uncoupling of benzodiazepine receptors to the GABAA receptor, thereby reversing tolerance and reducing withdrawal symptoms and relapse rates. Because of limited research and experience compared to the possible risks involved, the flumazenil detoxification method is controversial and can only be done as an inpatient procedure under medical supervision. :Flumazenil was found to be more effective than placebo in reducing feelings of hostility and aggression in patients who had been free of benzodiazepines for 4–266 weeks. This may suggest a role for flumazenil in treating protracted benzodiazepine withdrawal symptoms. :A study into the effects of the benzodiazepine receptor antagonist, flumazenil, on benzodiazepine withdrawal symptoms persisting after withdrawal was carried out by Lader and Morton. Study subjects had been benzodiazepine-free for between one month and five years, but all reported persisting withdrawal effects to varying degrees. Persistent symptoms included clouded thinking, tiredness, muscular symptoms such as neck tension, depersonalisation, cramps and shaking and the characteristic perceptual symptoms of benzodiazepine withdrawal, namely, pins and needles feeling, burning skin, pain and subjective sensations of bodily distortion. Therapy with 0.2–2 mg of flumazenil intravenously was found to decrease these symptoms in a placebo-controlled study. This is of interest as benzodiazepine receptor antagonists are neutral and have no clinical effects. The author of the study suggested the most likely explanation is past benzodiazepine use and subsequent tolerance had locked the conformation of the GABA-BZD receptor complex into an inverse agonist conformation, and the antagonist flumazenil resets benzodiazepine receptors to their original sensitivity. Flumazenil was found in this study to be a successful treatment for protracted benzodiazepine withdrawal syndrome, but further research is required. A study by Professor Borg in Sweden produced similar results in patients in protracted withdrawal. In 2007, Hoffmann–La Roche the makers of flumazenil, acknowledged the existence of protracted benzodiazepine withdrawal syndromes, but did not recommended flumazenil to treat the condition. • Fluoroquinolone antibiotics have been noted to increase the incidence of a CNS toxicity from 1% in the general population, to 4% in benzodiazepine-dependent population or in those undergoing withdrawal from them. This is probably the result of their GABA antagonistic effects as they have been found to competitively displace benzodiazepines from benzodiazepine receptor sites. This antagonism can precipitate acute withdrawal symptoms, that can persist for weeks or months before subsiding. The symptoms include depression, anxiety, psychosis, paranoia, severe insomnia, paresthesia, tinnitus, hypersensitivity to light (photophobia) and sound (hyperacusis), tremors, status epilepticus, suicidal thoughts and suicide attempt. Fluoroquinolone antibiotics should be contraindicated in patients who are dependent on or in benzodiazepine withdrawal. NSAIDs have some mild GABA antagonistic properties and animal research indicate that some may even displace benzodiazepines from their binding site. However, NSAIDs taken in combination with fluoroquinolones cause a very significant increase in GABA antagonism, GABA toxicity, seizures, and other severe adverse effects. • Imidazenil has received some research for management of benzodiazepine withdrawal, but is not currently used in withdrawal. • Imipramine was found to statistically increase the discontinuation success rate. • Pregabalin may help reduce the severity of benzodiazepine withdrawal symptoms, and reduce the risk of relapse. • Propranolol was not found to increase the discontinuation success rate. • Trazodone was not found to increase the discontinuation success rate. Inpatient treatment Inpatient drug detox or rehabilitation facilities may be inappropriate for those who have become tolerant or dependent while taking the drug as prescribed, as opposed to recreational use. Such inpatient referrals may be traumatic for these individuals. ==Prognosis==

A 2006 meta-analysis found evidence for the efficacy of stepped care: minimal intervention (e.g. send an advisory letter, or meet a large number of patients to advise discontinuation), followed by systematic tapered discontinuation alone without augmentation if the first try was unsuccessful. One study found that after one year of abstinence from long-term use of benzodiazepines, cognitive, neurological and intellectual impairments had returned to normal. Those who had a prior psychiatric diagnosis had a similar success rate from a gradual taper at a two-year follow-up. Withdrawal from benzodiazepines did not lead to an increased use of antidepressants. Withdrawal process It can be too difficult to withdraw from short- or intermediate-acting benzodiazepines because of the intensity of the rebound symptoms felt between doses. Moreover, short-acting benzodiazepines appear to produce a more intense withdrawal syndrome. For this reason, discontinuation is sometimes carried out by first substituting an equivalent dose of a short-acting benzodiazepine with a longer-acting one like diazepam or chlordiazepoxide. Failure to use the correct equivalent amount can precipitate a severe withdrawal reaction. Benzodiazepines with a half-life of more than 24 hours include chlordiazepoxide, diazepam, clobazam, clonazepam, chlorazepinic acid, ketazolam, medazepam, nordazepam, and prazepam. Benzodiazepines with a half-life of less than 24 hours include alprazolam, bromazepam, brotizolam, flunitrazepam, loprazolam, lorazepam, lormetazepam, midazolam, nitrazepam, oxazepam, and temazepam. The recommended reduction rates range from 50% of the initial dose every week or so, to 10–25% of the daily dose every 2 weeks. A prolonged period of reduction for longer than six months should be avoided to prevent the withdrawal process from becoming a "morbid focus" for the person. Duration After the last dose has been taken, the acute phase of the withdrawal generally lasts for about two months although withdrawal symptoms, even from low-dose use, can persist for six to twelve months gradually improving over that period, Protracted withdrawal syndrome Protracted withdrawal syndrome refers to symptoms persisting for months or even years. A significant minority of people withdrawing from benzodiazepines, protracted withdrawal syndrome which can sometimes be severe. Symptoms may include tinnitus, psychosis, cognitive deficits, gastrointestinal complaints, insomnia, paraesthesia (tingling and numbness), pain (usually in limbs and extremities), muscle pain, weakness, tension, painful tremor, shaking attacks, jerks, dizziness and blepharospasm The causes of persisting symptoms are a combination of pharmacological factors such as persisting drug induced receptor changes, psychological factors both caused by the drug and separate from the drug and possibly in some cases, particularly high dose users, structural brain damage or structural neuronal damage. Symptoms continue to improve over time, often to the point where people eventually resume their normal lives, even after years of incapacity. The change in symptoms has been proposed to be due to changes in receptor sensitivity for GABA during the process of tolerance reversal. Protracted symptoms continue to fade over a period of many months or several years. There is no known cure for protracted benzodiazepine withdrawal syndrome except time, however, the medication flumazenil was found to be more effective than placebo in reducing feelings of hostility and aggression in patients who had been free of benzodiazepines for 4–266 weeks. This may suggest a role for flumazenil in treating protracted benzodiazepine withdrawal symptoms. ==Epidemiology==

The severity and length of the withdrawal syndrome is likely determined by various factors, including rate of tapering, length of use and dosage size, and possible genetic factors. Those who have a prior history of withdrawing from benzodiazepines may have a sensitized or kindled central nervous system leading to worsening cognition and symptomatology, and making each subsequent withdrawal period worse. ==Special populations==

Pediatrics A neonatal withdrawal syndrome, sometimes severe, can occur when the mother had taken benzodiazepines, especially during the third trimester. Symptoms include hypotonia, apnoeic spells, cyanosis, impaired metabolic responses to cold stress, and seizures. The neonatal benzodiazepine withdrawal syndrome has been reported to persist from hours to months after birth. A withdrawal syndrome is seen in about 20% of pediatric intensive care unit children after infusions with benzodiazepines or opioids. The likelihood of having the syndrome correlates with total infusion duration and dose, although duration is thought to be more important. Treatment for withdrawal usually involves weaning over a 3- to 21-day period if the infusion lasted for more than a week. Symptoms include tremors, agitation, sleeplessness, inconsolable crying, diarrhea and sweating. In total, over fifty withdrawal symptoms are listed in this review article. Environmental measures aimed at easing the symptoms of neonates with severe abstinence syndrome had little impact, but providing a quiet sleep environment helped in mild cases. The elimination half-life of diazepam and chlordiazepoxide, as well as other long half-life benzodiazepines, is twice as long in the elderly compared to younger individuals. Many doctors do not adjust benzodiazepine dosage according to age in elderly patients. ==See also==