Prevalence rates of epilepsy in the US is around 1.2% of the total population, accounting for more than 3 million Americans. Apart from this condition, almost 18% of the population are also known to be suffering from neuropathic pain. Treatment for the above conditions typically comprises anti-epileptic medication including Gabapentin. This anticonvulsant is not only effective but s known to be a better choice by virtue of the many advantages. It has relatively lesser adverse effects and a wide therapeutic index, making it a suitable choice for treatment. However, as in the case of all medications there are certain undesirable side effects due to the mechanism of action. Let’s take a good look at the side effects of Gabapentin and ways to mitigate the effects.
Drug overview and side effects of Gabapentin
Before we look at the side effects of Gabapentin it is important to look at the drug overview. Gabapentin, belonging to the anticonvulsant category of medications is typically prescribed for treating the following conditions – postherpetic neuralgia, peripheral neuropathic pain, and diabetic neuropathy. The medication is used either in combination with other medications/regimen as adjunctive therapy or is used exclusively as monotherapy for treating the conditions. The anti-epileptic is known to work by ensuring that specific excitatory neurotransmitters are prevented from release. As a result of this mechanism of action, it is preferred for treating or managing pathologic neurotransmission. This includes conditions such as seizures and neuropathic pain. It is important to note that the medication is intended for use in treating specific types of seizures and is not to be used for ‘absence seizures’ or mixed seizures that involve ‘absence seizures’.
Mechanism of action of gabapentin and side effects of Gabapentin
Though there is lack of clarity about the actual mechanism of action of Gabapentin, certain indications help understand the precise manner in which the anticonvulsant works. It is known to prevent the action of specific types of neurotransmitters. These neurotransmitters, classified as excitatory, typically trigger an action or a signal in the receiving neuron. Consequently, there is some action associated with the neurotransmitters. By inhibiting these excitatory neurotransmitters, Gabapentin brings about the anti-epileptic and anticonvulsant action. Gabapentin is also known to exert action on adenosine receptors; however, more studies are required for substantiation of this claimed action.
Side effects of Gabapentin : drug interactions
As we start looking at the side effects of Gabapentin, it is time to start with the drug interactions of Gabapentin. The medication can react with other prescription medications or products that are available over the counter, including supplements. Patients prescribed the medication are to exercise care while consuming large amounts of coffee, tea or colas. The presence of caffeine in these products may possibly react with the medication, and this could cause complications. Similarly, individuals on diuretics, such as ethacrynic acid need to consult the treating doctor, as certain adverse effects are likely to be experienced.
Other medications that have been recorded as having side effects include medication for high blood pressure medication belonging to the angiotensin II receptor blocker category, such as losartan. Pain medications with opioids such as morphine could also have undesirable effects. Finally, individuals on mineral supplements that contain magnesium oxide and other antacids are also cautioned about the side effects. The drug may also interact with other medication used for treating seizures, such as phenytoin, and it is therefore necessary to check the type of medications used as combination/adjunctive therapy.
One of the side effects of Gabapentin is drowsiness, and therefore, individuals on certain types of medications need to consult a specialist. When other medications that cause drowsiness are taken alongside Gabapentin, the combined effects on sleep can be strong and it is therefore necessary to speak to the doctor about changing the medication or the dosage/timing. Whenever a patient is expected to drop and medication that has a drug interaction with another formulation, the patient typically chooses to retain the one that is more important. In other words, the medication for treating a condition that is more severe or serious in nature, will be retained and the medication for treating less severe conditions will either be dropped or the dosage is altered. Individuals on medications for treating anxiety disorders and for depression need to adopt the above practice. Similarly, individuals on antihistamines, and formulations for muscle relaxation are also to seek medical advice. Pain medications that contain opioids, and medications used for inducing sleep, will interact with Gabapentin. Finally, individuals on any prescription or over the counter formulations for treating flu or cold are also directed to seek medical advice.
Pre-existing issues in patients and side effects of Gabapentin
To prevent the side effects of Gabapentin from adversely impacting individuals with pre-existing health conditions, patients are advised to list out all conditions before treatment. For instance, individuals undergoing dialysis are to inform the treating specialist of the condition, as Gabapentin side effects may end up with adverse results. Similarly, patients with breathing difficulties or complications, and a history of any kind of drug/alcohol or intoxicant abuse are to specifically mention the issue to the doctor. Diabetics and patients with heart ailments are also at risk of experiencing unwanted side effects of Gabapentin. Individuals with existing impaired renal functions, or liver disease are also cautioned to seek medical advice before taking the drug. Gabapentin is prescribed for treating various conditions, and if a patient with a history of seizures is taking the drug for some condition other than seizures, the same is to be intimated to the treating specialist. Finally, patients diagnosed with mental health conditions and/or depression are also at risk of experiencing side effects of the drug and are therefore expected to seek medical advice.
Pregnant women and women breastfeeding children
There are possible side effects of Gabapentin on pregnant women and women breastfeeding children. It is therefore necessary for women who are either pregnant or planning a pregnancy to intimate the same to the treating specialist. Typically, pregnant women are prescribed the medication only when it is entirely necessary for the drug to be taken. Women with a history of seizures may require the medication, as it is extremely important to avoid and control seizures during any stage of pregnancy. The commencement or the discontinuation of the anti-epileptic drug by pregnant women is to be only under medical supervision. This follows a process of assessment of the various benefits from the drug and the risks associated with the mechanism of action of the medication. Women who are breastfeeding infants are also expected to seek medical advice, as the drug is known to be present in breast milk, when the mother is on the medication. However, the consequences of the drug in milk and babies are yet to be studied conclusively. It is therefore important to seek medical advice regarding the anti-epileptic to avoid side effects of Gabapentin.
Commonly reported side effects of Gabapentin
It is now time to look at commonly reported side effects of Gabapentin. Various studies have been conducted in the past to assess and determine the extent of side effects of the medication on participants. In one of the studies, around ten percent participants reported feelings of dizziness. In the same study, participants also reported feelings of drowsiness from the medication. Some of the other side effects include water retention, while others have reportedly experienced difficulty while walking. The water retention was mainly observed in the arms, feet and legs, that were visible as swelling.
Side effects of Gabapentin are classified into common, frequent effects that are not serious in nature and effects that could be adverse or serious in nature. The serious effects are generally rare in terms of occurrence when compared with the common effects. Among the serious side effects, the most frequently reported include back pain and chest pain. Pain that is not attributed to other conditions when on the medication is one of the serious side effects. .Additionally, some patients reported constipation when on the medication. This was recorded in patients who were on the medication for a long term. Other side effects of Gabapentin that are serious in nature include diarrhea, vomiting. Some of the side effects are linked to long term use only, such as upset stomach, reported by patients. Some side effects have long lasting impact on patients. In other words, the side effects are known to last long and will require some kind of action to reverse the condition. For instance, weight gain and a sudden increase in appetite is reported among patients on the medication, and the effects of this will last long, unless reversed with suitable actions. Some patients are known to experience blurred vision, while others have reported unexplained mood swings.
There are other conditions that are not serious in nature, though the effects require care. For instance, patients are known to be exposed to more bruising, when on the medication, while others experience abnormal tiredness. Bouts of coughing are also associated with the medication. Side effects of Gabapentin also include the possibility of running a fever, experiencing dry mouth, or ending up with a hoarse voice. Patients are also known to lose memory, while some exhibit symptoms similar to cold and flu. Other conditions that are associated with the medication include difficulty in breathing, problems experienced during urination, and hard to manage eye-rolling.
Children and commonly reported side effects of Gabapentin
Side effects of Gabapentin have been reported in children, and this includes certain reactions that are adverse in nature. These side effects are typically not frequently occurring. Some of the reactions include a change in mood, anxiety or depression. Behavioral issues are often linked to long-use of Gabapentin in children. This could also impact the performance of children in academics. An impact on concentration and focus of children has been reported, in addition to causing hyperactivity among the affected. Parents with children who have been prescribed the medication are advised to speak to specialists to understand more about the medication and its side effects. Whenever behaviour or issues are serious in nature, the treating specialist is to be intimated to help initiated appropriate medical care.
Side effects of Gabapentin that are serious in nature
There are certain side effects of Gabapentin that may require attention or triage from a medical team or at a specialist facility. For instance, severe allergic reactions or life-threatening difficulties in breathing require emergency care. Patients are likely to experience breathing difficulties, very severe dizziness and strong allergic reactions. This is most likely to have an effect on normal routines, when the patient has responsibilities that include the handling of heavy machinery or equipment that require constant attention. Another condition that needs to be handled with care includes fever that is not controlled through medication. Other possible side effects that require medical treatment include severe allergic reactions, rashes and hives. It is necessary to check and avail necessary treatment at the earliest before the allergies turn serious in nature.
Other possible side effects of Gabapentin include weakness, discoloration of the skin and eyes. These conditions are similar to that of symptoms experienced when a patient has jaundice. Whenever these visible symptoms are observed, it is necessary to undergo tests and avail appropriate treatment so as to control the condition. Any inflammation or swelling in the face is also a cause for concern. This could typically be in the face, throat, lips and tongue and appear as swelling.
Certain pre-existing conditions in patients could result in side effects that are serious or adverse in nature. For instance, as mentioned in above sections, women planning a pregnancy, or breastfeeding mothers, patients with breathing difficulties, individuals with type 2 diabetes, patients with kidney or liver disease, are at risk of experiencing side effects of Gabapentin. Another category of patients who may experience side effects are those undergoing dialysis.
Preventing side effects of Gabapentin by sticking to the right dosage and practices
One of the best methods of handling side effects is to follow the right practices and stick to the right dosage as recommended. This will prevent side effects of Gabapentin. Various aspects that need to be checked include the brand and the strength of dosage. One of the reasons why this is to be checked is the fact that different brands generally manufacture formulations in possibly different standard dosages. Gabapentin has an impact on the kidneys and it is necessary understand the patient’s kidney condition. Other factors that determine the dosage include weight, age and the health of the patient. In addition to the above, the number of doses, the time between two doses and the expected length of treatment with medication are also to be considered. Depending on the condition, the medication may have to be taken with food, though it is not necessary always.
When it comes to dosage, it is necessary to understand that certain formulations are to be taken only in the evenings/or the nights. At times the dosage may be less, and it may be necessary to split the tablets into two. In such situations, use a proper pill cutter and ensure that the other half of the tablet is taken as the next dose, with proper storage. Never break or chew extended-release formulations, as these tablets are meant to be taken fully. Dosages should never be exceeded, and ensure that the prescribed dosages are always followed. Also, the period of treatment should be as per the specific recommendations of the medical practitioner.
Overdose and toxicity
Gabapentin has a wide therapeutic index, which makes it safe for use. However, despite the tag of a safe or benign adverse effect profile, excessive dosage could result in adverse reactions and side effects. Overdose effects are similar to that of side effects of Gabapentin as mentioned above. For instance, CNS depression is one of the more common side effects of overdose. This is consistent with the side effects mentioned in previous sections. Other possible adverse reactions of overdose include gastrointestinal symptoms. The commonly experienced CNS depression – feelings of dizziness and a sudden loss of consciousness may or may not be accompanied by laziness. Individuals may exhibit lethargy, with a marked slurred speech.
The common gastrointestinal symptoms include diarrhea and possible vomiting. Overdose is generally managed in a manner that tackles the symptoms of overdose. It could also be supportive in nature so as to mitigate the overdose effects. Hemodialysis is a possible method of removing excessive amounts of the drug. One additional positive outcome of hemodialysis is the benefit to patients suffering from kidney related problems. Overdose treatment typically follows a procedure wherein the possibility of overdose of other medications or opioids is also considered. Multi-drug overdose is a possibility in certain cases, and the treatment for such multi-drug overdoses demands additional precautions. This is necessary as coma or fatality is a possibility. Though this is a rare occurrence the possibility cannot be ruled out and it is therefore necessary to follow the right procedures.