Gabapentin is an anticonvulsant or antiepileptic drug, with off-label use as anxiolytic in the treatment of anxiety disorders. It is also found to be effective in the treatment of neuropathic pain. Brand names for gabapentin include Neurontin, Horizant, and Gralise.
Mechanism of Action of Gabapentin
Gabapentin increases the concentration of the neurotransmitter gamma-aminobutyric acid (GABA) by increasing the activity of the enzyme glutamate decarboxylase (GAD). Neurotransmitters are chemical messengers relaying signals between nerve cells. Gabapentin binds to the calcium ion channels in the spine and brain, and thus reduces the abnormal brain activity that causes seizures, tremors, and pain.
Dose of Gabapentin
The therapy will be started at 300 mg/day. The dose will then be increased every 3 to 5 days, going up to 900 mg/day, or even up to 4,800 mg/day in some people.
Gabapentin is not metabolized in humans and is excreted unchanged, mainly in the urine. Gabapentin has a half-life of about six hours, so it must be administered 3 to 4 times a day. It takes anywhere between a week and a month for gabapentin to work.
Uses of Gabapentin
Gabapentin finds use in controlling seizures in patients with drug-resistant epilepsy as well as focal epilepsy.
A few studies show that gabapentin has been a successful treatment for individuals who suffer from anxiety. However, since the effectiveness of gabapentin for the treatment of anxiety disorders is mild for most individuals, it is probably best used in conjunction with other treatments for anxiety.
Gabapentin has been found to help individuals manage their anxiety and improve their sleep habits when they suffer from disorders such as panic disorder, alcohol dependencies, obsessive-compulsive disorder (OCD), and drug dependencies, we well as individuals with schizophrenia and bipolar disorder.
Gabapentin has positive results in the treatment of neuropathic pain. Neuropathic pain is pain caused by nerve damage. It also affords relief from pain in diseases such as fibromyalgia, sciatica, and multiple sclerosis.
Gabapentin also finds off-label use in conditions such as alcohol withdrawal, cocaine withdrawal, restless leg syndrome, hiccups, and hot flashes.
Side Effects of Gabapentin
Common side effects are:
- Double Vision
- Impaired memory
- Involuntary eye movements
- Fluid retention
- Difficulty speaking
- Jerky movements
- Nausea and/or vomiting
- Weight gain
- Motion sickness
- Joint pains
Rare side effects include:
- Increased risk of suicidal thinking and behavior
- Increased or decreased libido
Overdosing, Withdrawal and Other Safety Issues
People have survived overdoses of up to 49,000 mg of gabapentin without any serious consequences.
You should not abruptly discontinue the use of gabapentin. Abrupt withdrawal of the drug puts you at high risk for anxiety, insomnia, and nausea.
Alcohol may increase the discomfort of gabapentin’s side effects.
Gabapentin has been placed in pregnancy category C by the FDA. Animal studies show that there was harm done to fetuses. No studies have been done on humans. Experts believe that the benefits of taking gabapentin may outweigh its risks.
Gabapentin is not approved for use in children below the age of 12.
Interactions with Gabapentin
Not many interactions have been brought to light. Gabapentin increases the concentration of oral contraceptives by around 10%. Antacids decrease its absorption, and decrease its blood level by 20%. Therefore, gabapentin should be administered 2 hours or more after taking antacids. Morphine increases blood concentrations of gabapentin and central nervous system-related adverse events associated with gabapentin.