Prescription Drug Information: Gabapentin (Page 4 of 6)
Incidence in Controlled Clinical Trials
Table 2 lists treatment-emergent signs and symptoms that occurred in at least 1% of gabapentin-treated patients with postherpetic neuralgia participating in placebo-controlled trials and that were numerically more frequent in the gabapentin group than in the placebo group. Adverse events were usually mild to moderate in intensity.
Body System/ Preferred Term | GabapentinN=336% | PlaceboN=227% |
---|---|---|
| ||
Body As A Whole | ||
Asthenia | 5.7 | 4.8 |
Infection | 5.1 | 3.5 |
Headache | 3.3 | 3.1 |
Accidental injury | 3.3 | 1.3 |
Abdominal pain | 2.7 | 2.6 |
Digestive System | ||
Diarrhea | 5.7 | 3.1 |
Dry mouth | 4.8 | 1.3 |
Constipation | 3.9 | 1.8 |
Nausea | 3.9 | 3.1 |
Vomiting | 3.3 | 1.8 |
Flatulence | 2.1 | 1.8 |
Metabolic and Nutritional Disorders | ||
Peripheral edema | 8.3 | 2.2 |
Weight gain | 1.8 | 0.0 |
Hyperglycemia | 1.2 | 0.4 |
Nervous System | ||
Dizziness | 28.0 | 7.5 |
Somnolence | 21.4 | 5.3 |
Ataxia | 3.3 | 0.0 |
Thinking abnormal | 2.7 | 0.0 |
Abnormal gait | 1.5 | 0.0 |
Incoordination | 1.5 | 0.0 |
Amnesia | 1.2 | 0.9 |
Hypesthesia | 1.2 | 0.9 |
Respiratory System | ||
Pharyngitis | 1.2 | 0.4 |
Skin and Appendages | ||
Rash | 1.2 | 0.9 |
Special Senses | ||
Amblyopia * | 2.7 | 0.9 |
Conjunctivitis | 1.2 | 0.0 |
Diplopia | 1.2 | 0.0 |
Otitis media | 1.2 | 0.0 |
Other events in more than 1% of patients but equally or more frequent in the placebo group included pain, tremor, neuralgia, back pain, dyspepsia, dyspnea, and flu syndrome.
There were no clinically important differences between men and women in the types and incidence of adverse events. Because there were few patients whose race was reported as other than white, there are insufficient data to support a statement regarding the distribution of adverse events by race.
Epilepsy
The most commonly observed adverse events associated with the use of gabapentin in combination with other antiepileptic drugs in patients >12 years of age, not seen at an equivalent frequency among placebo-treated patients, were somnolence, dizziness, ataxia, fatigue, and nystagmus. The most commonly observed adverse events reported with the use of gabapentin in combination with other antiepileptic drugs in pediatric patients 3 to 12 years of age, not seen at an equal frequency among placebo-treated patients, were viral infection, fever, nausea, and/or vomiting, somnolence, and hostility (see WARNINGS, Neuropsychiatric Adverse Events).
Approximately 7% of the 2074 patients >12 years of age and approximately 7% of the 449 pediatric patients 3 to 12 years of age who received gabapentin in premarketing clinical trials discontinued treatment because of an adverse event. The adverse events most commonly associated with withdrawal in patients >12 years of age were somnolence (1.2%), ataxia (0.8%), fatigue (0.6%), nausea and/or vomiting (0.6%), and dizziness (0.6%). The adverse events most commonly associated with withdrawal in pediatric patients were emotional lability (1.6%), hostility (1.3%), and hyperkinesia (1.1%).
Incidence in Controlled Clinical Trials
Table 3 lists treatment-emergent signs and symptoms that occurred in at least 1% of gabapentin-treated patients >12 years of age with epilepsy participating in placebo-controlled trials and were numerically more common in the gabapentin group. In these studies, either gabapentin or placebo was added to the patient’s current antiepileptic drug therapy. Adverse events were usually mild to moderate in intensity.
The prescriber should be aware that these figures, obtained when gabapentin was added to concurrent antiepileptic drug therapy, cannot be used to predict the frequency of adverse events in the course of usual medical practice where patient characteristics and other factors may differ from those prevailing during clinical studies. Similarly, the cited frequencies cannot be directly compared with figures obtained from other clinical investigations involving different treatments, uses, or investigators. An inspection of these frequencies, however, does provide the prescribing physician with one basis to estimate the relative contribution of drug and nondrug factors to the adverse event incidences in the population studied.
Body System/ Adverse Event | Gabapentin *N=543% | Placebo *N=378% |
---|---|---|
Body As A Whole | ||
Fatigue | 11.0 | 5.0 |
Weight Increase | 2.9 | 1.6 |
Back Pain | 1.8 | 0.5 |
Peripheral Edema | 1.7 | 0.5 |
Cardiovascular | ||
Vasodilatation | 1.1 | 0.3 |
Digestive System | ||
Dyspepsia | 2.2 | 0.5 |
Mouth or Throat Dry | 1.7 | 0.5 |
Constipation | 1.5 | 0.8 |
Dental Abnormalities | 1.5 | 0.3 |
Increased Appetite | 1.1 | 0.8 |
Hematologic and Lymphatic Systems | ||
Leukopenia | 1.1 | 0.5 |
Musculoskeletal System | ||
Myalgia | 2.0 | 1.9 |
Fracture | 1.1 | 0.8 |
Nervous System | ||
Somnolence | 19.3 | 8.7 |
Dizziness | 17.1 | 6.9 |
Ataxia | 12.5 | 5.6 |
Nystagmus | 8.3 | 4.0 |
Tremor | 6.8 | 3.2 |
Nervousness | 2.4 | 1.9 |
Dysarthria | 2.4 | 0.5 |
Amnesia | 2.2 | 0.0 |
Depression | 1.8 | 1.1 |
Thinking Abnormal | 1.7 | 1.3 |
Twitching | 1.3 | 0.5 |
Coordination Abnormal | 1.1 | 0.3 |
Respiratory System | ||
Rhinitis | 4.1 | 3.7 |
Pharyngitis | 2.8 | 1.6 |
Coughing | 1.8 | 1.3 |
Skin and Appendages | ||
Abrasion | 1.3 | 0.0 |
Pruritus | 1.3 | 0.5 |
Urogenital System | ||
Impotence | 1.5 | 1.1 |
Special Senses | ||
Diplopia | 5.9 | 1.9 |
Amblyopia † | 4.2 | 1.1 |
Laboratory Deviations | ||
WBC Decreased | 1.1 | 0.5 |
Other events in more than 1% of patients >12 years of age but equally or more frequent in the placebo group included: headache, viral infection, fever, nausea and/or vomiting, abdominal pain, diarrhea, convulsions, confusion, insomnia, emotional lability, rash, acne.
Among the treatment-emergent adverse events occurring at an incidence of at least 10% of gabapentin treated patients, somnolence and ataxia appeared to exhibit a positive dose-response relationship.
The overall incidence of adverse events and the types of adverse events seen were similar among men and women treated with gabapentin. The incidence of adverse events increased slightly with increasing age in patients treated with either gabapentin or placebo. Because only 3% of patients (28/921) in placebo-controlled studies were identified as nonwhite (black or other), there are insufficient data to support a statement regarding the distribution of adverse events by race.
Table 4 lists treatment-emergent signs and symptoms that occurred in at least 2% of gabapentin-treated patients age 3 to 12 years of age with epilepsy participating in placebo-controlled trials and were numerically more common in the gabapentin group. Adverse events were usually mild to moderate in intensity.
Body System/ Adverse Event | Gabapentin *N=119% | Placebo *N=128% |
---|---|---|
| ||
Body As A Whole | ||
Viral Infection | 10.9 | 3.1 |
Fever | 10.1 | 3.1 |
Weight Increase | 3.4 | 0.8 |
Fatigue | 3.4 | 1.6 |
Digestive System | ||
Nausea and/or Vomiting | 8.4 | 7.0 |
Nervous System | ||
Somnolence | 8.4 | 4.7 |
Hostility | 7.6 | 2.3 |
Emotional Lability | 4.2 | 1.6 |
Dizziness | 2.5 | 1.6 |
Hyperkinesia | 2.5 | 0.8 |
Respiratory System | ||
Bronchitis | 3.4 | 0.8 |
Respiratory Infection | 2.5 | 0.8 |
Other events in more than 2% of pediatric patients 3 to 12 years of age but equally or more frequent in the placebo group included: pharyngitis, upper respiratory infection, headache, rhinitis, convulsions, diarrhea, anorexia, coughing, and otitis media.
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