Effectiveness Not Established

Gabapentin

for Anxiety

Gabapentin, which belongs to the class of medications called anticonvulsants, treats seizures by decreasing excitement in the brain. Gabapentin has been studied for its effect in patients with cancer who have neuropathic pain or symptoms of peripheral neuropathy. The drug changes the way the body senses pain. It has also been studied for its effect on anxiety, chemotherapy-induced nausea and vomiting, and hot flashes.

The U.S. Food and Drug Administration (FDA) has issued a warning regarding the use of gabapentin or pregabalin and serious breathing difficulties in people with respiratory risk factors, including older adults, those having conditions that reduce lung function such as chronic obstructive pulmonary disease (COPD), and those using drugs that depress the central nervous system including opioids, anti-anxiety medication, antidepressants, and antihistamines.

Research Evidence Summaries

Lavigne, J.E., Heckler, C., Mathews, J.L., Palesh, O., Kirshner, J.J., Lord, R., . . . Mustian, K. (2012). A randomized, controlled, double-blinded clinical trial of gabapentin 300 versus 900 mg versus placebo for anxiety symptoms in breast cancer survivors. Breast Cancer Research and Treatment, 136, 479–486.

Study Purpose

To compare the efficacy of gabapentin 300 mg and 900 mg for controlling anxiety symptoms among breast cancer survivors

Intervention Characteristics/Basic Study Process

Patients were randomly assigned to receive 300 mg or 900 mg of gabapentin or placebo daily. Outcomes were assessed at baseline, four weeks, and eight weeks.

Sample Characteristics

  • The study reported on a sample of 420 female patients with breast cancer.
  • Mean patient age was 55 years.
  • All patients had completed initial therapy.
  • More than 75% of patients were married, and about 70% were on tamoxifen.
  • All patients had at least two hot flashes per day for seven days prior to enrollment.

Setting

  • Single site
  • Outpatient setting
  • Rochester Cancer Center

Phase of Care and Clinical Applications

Patients were undergoing the transition phase of care after initial treatment.

Study Design

A double-blind, placebo-controlled, randomized controlled trial design was used.

Measurement Instruments/Methods

  • Strait-Trait Anxiety Inventory
  • MD Anderson Symptom Inventory

Results

At four weeks, patients on gabapentin showed significant reduction in anxiety scores (p = 0.005). Patients with the highest baseline anxiety scores had the greatest improvement, and those with low anxiety levels had little change. These patterns were maintained at the eight-week follow-up. The greatest improvement in anxiety was seen in those getting 300 mg of gabapentin. Anxiety scores of those on placebo also declined, but changes were not significant.

Conclusions

 Gabapentin 300 mg daily was effective in reducing symptoms of anxiety in these breast cancer survivors.

Limitations

  • Findings are not generalizable.
  • The sample was women who also had hot flash symptoms; the mechanism of action of gabapentin has been associated with mechanisms causing hot flashes, so this may not have the same effect in women who do not have hot flash symptoms.

Nursing Implications

This study demonstrated that 300 mg of gabapentin daily was effective in controlling anxiety symptoms among breast cancer survivors who had been experiencing hot flashes and had relatively high baseline anxiety. Gabapentin is currently off label in psychiatry to treat anxiety symptoms and commonly used to treat hot flashes and neuropathic pain in breast cancer survivors. As shown in other research, improvement in anxiety symptoms tends to be found in patients who have clinically relevant levels of anxiety to begin with. Nurses can consider and advocate for use of gabapentin to manage anxiety in these patients.

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