Benzodiazepine Withdrawal Syndrome
As we age, our appearance changes with brown hair replaced by gray and smooth skin by wrinkles. What is not evident from the outside is the changing pharmacokinetics and pharmacodynamics on the inside. For any aging person taking medications, the changes in drug absorption, distribution, metabolism, and excretion along with changes in receptor affinity and volume of distribution may be overlooked, but are vital when selecting a drug for an elderly patient. These alterations place the aging population at risk for adverse drug events and effects due to drug withdrawal.
Benzodiazepines, which include diazepam, lorazepam, chlordiazepoxide, oxazepam and others, are drugs whose abrupt withdrawal can cause important adverse effects. Benzodiazepines have a multi-factorial mechanism of action. The primary mechanism is binding to chloride channels that facilitate the effects of γ-aminobutyric acid also called GABA. Ethanol also interacts with this receptor. Some studies show that benzodiazepines lead to decreased serotonergic and adrenergic activity in addition to the primary effects on chloride channels. Sudden withdrawal of these medications may cause a variety of symptoms related to the neurotransmitters affected by benzodiazepines. These effects are due to the sudden increase of serotonin, norepinephrine, or glutamate at central and peripheral nervous system receptors. The withdrawal syndrome may be fast or slow in onset due to the pharmacokinetic properties of the specific drug used, such as its half-life and the presence or absence of active metabolites. In the geriatric population, the onset may be slower compared to what is seen in younger adults due to the patient's delayed metabolism and excretion of drugs.
Many studies have shown a wide range of symptoms with the sudden withdrawal of benzodiazepines. The most serious effect is seizure activity. Other symptoms observed with benzodiazepine withdrawal are:
- Perceptual distortions
- Difficulty walking
- Gastrointestinal disturbances
- Headache
- Tremor
- Autonomic instability
- Sensitivity to light, noise, taste, smell
- Sleep disturbances
- Anxiety
- Tension
- Agitation
- Restlessness
While benzodiazepine withdrawal syndromes are self limiting, the effects produced can be difficult to identify as such. In the geriatric patient, these symptoms may be reported as delirium, Parkinson"s, or other "geriatric syndromes." It is therefore important to obtain a medication history at each visit, as few geriatric patients are treated by only one physician. Patients on long-standing prescriptions of benzodiazepines should receive a gradual dosage taper done over several weeks. As health care providers to the geriatric community, we must remember that our patients are notorious for presenting with atypical symptoms in every situation.
References
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