Gabapentin side effects in elderly patients

Common Gabapentin side effects | Serious side effects | Side effects timeline | Interactions | Safety | How to avoid side effects | How to treat side effects

Gabapentin has become a common prescription medication, largely because of off-label prescribing. While the Food and Drug Administration (FDA) has approved it for the treatment of partial seizures and postherpetic neuralgia (nerve pain after shingles), but there are several other off-label uses. The list includes anxiety, chronic neuropathic pain, and restless leg syndrome. These diagnoses are not uncommon among older adults, so it is not hard to imagine scenarios in which gabapentin may be prescribed to seniors. With this in mind, we will focus on cautionary points about gabapentin’s side effects and negative outcomes from the drug that could pose more risk to older patients.

Common side effects of gabapentin 

Gabapentin’s common adverse effects fall into two major categories: physical effects like dizziness and cognitive effects like confusion. Those are of paramount importance in older adults and warrant further research.

Physical side effects of gabapentin in the elderly

The biggest concern regarding the physical side effects of gabapentin in seniors involves reactions that pose a heightened risk of falls. The fear is well-founded, considering that the FDA drug label lists the prevalence of dizziness at 28%, impaired walking at 3%, abnormal walking at 2%, and incoordination at 2% among those taking gabapentin. Those can all be risk factors for falls and injuries, particularly in older patients. Some other physical side effects are worth pointing out and include:

• Peripheral edema (leg swelling)
• Nausea and vomiting
• Diarrhea or constipation
• Erectile dysfunction

Cognitive side effects of gabapentin in the elderly

Equally concerning for older adults is the chance of cognitive side effects. The drug label cites a 19% rate of somnolence (excessive drowsiness), a 2% rate of amnesia, and a 2% rate of abnormal thinking among those taking gabapentin in clinical trials. Other cognitive side effects include memory impairment and fatigue.

Emotional and psychological side effects of gabapentin in the elderly

Although, at face value, they may seem of lesser importance, the emotional and psychological side effects of gabapentin in older people can be just as important as the physical and cognitive ones. The incidence of depression with gabapentin is listed at 2% on the drug label. Suicidal thoughts while on gabapentin are not considered common, but this possibility has been the subject of case reports and reviews.

Serious side effects of gabapentin 

Suicidality is just one of the potentially serious adverse effects that can happen while taking gabapentin. Other serious side effects include:

• Seizures during withdrawal from the drug
• Withdrawal syndrome
• Respiratory depression (a less natural drive to breathe)
• Stevens-Johnson syndrome (severe drug-related illness and rash)
• Anaphylaxis and allergic reactions

How soon do gabapentin side effects start?

Side effects from gabapentin are typically experienced soon after initiating it or increasing the dose. The adverse effects are often apparent early in treatment—some within hours and some within days.

How long do gabapentin side effects last?

Many of gabapentin’s side effects can persist as long as you are taking the drug. However, mild side effects like drowsiness or nausea can resolve within a week or two, even if the medication is continued. Talk to your healthcare provider to find out what you should do and whether you should avoid driving and other tasks that require sustained attention.

What are the long-term side effects of gabapentin?

Of most concern long-term, a potential for dependence and misuse exists with gabapentin. If your body has developed a dependence on the drug, you could have a withdrawal syndrome if you stop gabapentin suddenly. Withdrawal symptoms might include anxiety, confusion, sweating, and even seizures, potentially. 

Misuse of gabapentin stems from the euphoria that some feel from the use of the drug, and that drives them to use it in ways and doses beyond what is prescribed. The rate of misuse may be as low as 1% amongst general users of the medication or as high as 22% in those who have other drug addictions. Excessive doses raise the risk of respiratory depression, which is life-threatening if breathing slows too much. This critical issue is typically tied to other drugs that depress the central nervous system (CNS).

Gabapentin interactions

As the length of one’s medication list increases, the chance of a significant interaction between drugs rises as well. This risk is especially important to older adults due to the greater number of medications being taken in general. Here are some of the major interactions with gabapentin to be aware of.

• CNS depressants fall under a large umbrella category with numerous subcategories of concern. The most noteworthy include opioids, benzodiazepines, antihistamines, drugs for insomnia, and other anticonvulsant medications. Combining gabapentin with these types of medications can heighten the risk of side effects like drowsiness or, in severe cases, lead to respiratory depression.
• Antidepressants and muscarinic antagonists are two other drug classes that may not be thought of as CNS depressants at first glance, but they do have this potential. Therefore, their risk, in combination with gabapentin, warrants caution.
• Alcohol and cannabinoids are CNS depressants. They magnify many of the adverse effects of gabapentin and create a danger to those taking the drug.

Safety measures while using gabapentin

Besides drug interactions, older patients have to be conscientious about whether a prescription drug could negatively interact with any of their health conditions. Gabapentin is no exception, as evidenced by the following conditions and situations.

Kidney disease

Gabapentin is eliminated from the body by the kidney. It makes sense then that impaired renal function could lead to the accumulation of the drug. Your healthcare provider may advise adjusting the dose if you have a reduced kidney function, a not uncommon issue facing seniors and one that you may not be aware of. A low dose of gabapentin may still be safe.

Myasthenia gravis

Myasthenia gravis is a neurologic disease marked by muscle weakness. Adding gabapentin could exacerbate the condition.

Substance abuse history

For those with a history of substance abuse, the risk of gabapentin misuse or abuse is higher. Accordingly, your medical team may discuss alternatives to gabapentin to lessen this risk.

Depression and suicidality

Use of seizure medication, including gabapentin, has been linked to a higher risk of suicidal thoughts. Seniors are not immune to this issue, considering the suicide rate increases with age among people ages 55 and older. Tell your doctor if you are having any thoughts of hurting yourself or call the National Suicide & Crisis Lifeline at 988.

Withdrawal

Long-term gabapentin therapy can result in physical dependence on the drug. With that, there is a chance of withdrawal when it is stopped. The medical reference UpToDate lists some of the possible withdrawal symptoms as sweating, abdominal pain, diarrhea, shakiness, fast heart rate, elevated blood pressure, agitation, confusion, and hallucinations, as well as a chance of seizures. If you are thinking of quitting the drug because of its expense, first look into coupons for brand-name Neurontin or generic gabapentin. 

Overdose

Overdose of gabapentin is dangerous, even more so for those taking other CNS depressants or with kidney disease. While the maximum dose is listed at 3,600 milligrams, the dosing threshold for major adverse reactions could be lower in seniors with reduced kidney function or taking medications that interact with gabapentin. 

Neurologic signs of overdose include drowsiness and lethargy. The risk of fatal respiratory depression is of most concern, typically with higher doses or in combination with other drugs. Highlighting this is the statistic that the use of gabapentin increased the risk of opioid-associated death by 60%. An overdose of gabapentin should lead to an immediate call for emergency medical attention.

How to avoid gabapentin side effects

You can reduce the risk of gabapentin side effects by doing the following:

1. Take gabapentin exactly as it is prescribed to you, taking steps to avoid missed doses and being sure not to increase or adjust the dosing without consulting your prescribing healthcare professional for medical advice.
2. Although you can take gabapentin with or without food, Gralise (the extended-release gabapentin product) must be taken with food.
3. If you are taking gabapentin only once a day, it may be best to take it at bedtime to avoid drowsiness during the daytime.
4. Do not stop taking gabapentin on your own. Instead, get your doctor’s advice on whether to stop it and how best to taper off the drug.
5. Go over your list of different medicines, over-the-counter drugs, and supplements with your healthcare team prior to starting gabapentin and periodically during treatment to make sure you are not risking an interaction.
6. Keep your medical providers and pharmacists updated on your medical history to help ensure that gabapentin is not going to be more problematic based on a health condition, such as in the presence of chronic kidney disease.
7. Work with your doctor so that you can make use of the lowest dose of gabapentin that is still effective.
8. Avoid alcohol while taking gabapentin.

How to treat side effects of gabapentin

Gabapentin side effects span a spectrum from mild to severe. Being a little sleepy after first initiating the drug may only require observation to see if it resolves in a few days, whereas changes in mental status, unsteadiness, and trouble breathing require more immediate action. Consult your healthcare provider to help decide what to do if you experience an adverse effect.

Bottom line: Is gabapentin safe for older adults?

Gabapentin can be a safe medication for older adults. Knowing what side effects to watch for, which drugs interact with it, and what health conditions influence the risk is the first step to take toward mitigating the risk of gabapentin side effects and interactions. Now that you are more aware of these issues, you can take the next step by having a detailed conversation with your medical provider to confirm whether gabapentin is the best choice for you and ask what more you can do to stay safe while using gabapentin.