Overview
- Gabapentinoids, such as gabapentin and pregabalin, are a class of medication used to treat epilepsy and nerve pain
- There are some risks associated with taking gabapentinoids, with common side effects including drowsiness and dizziness. More severe side effects can include hallucinations and suicidal thoughts
- Growing concerns surround the misuse of gabapentinoids, with some patients becoming addicted
What are gabapentinoids?
Gabapentinoids are a class of medications used to treat epilepsy and neuropathic pain. Examples of gabapentinoids include gabapentin and pregabalin, which may be prescribed to patients to treat:
- Epilepsy
- Nerve pain caused by an injury, shingles (post-herpetic neuralgia), diabetes, or restless leg syndrome
- Symptoms of multiple sclerosis
- Anxiety
Gabapentinoids are available in both tablet and liquid form.
How do gabapentinoids work?
Gabanepenitoids play a role in regulating the release of neurotransmitters, helping to block nerve pain as a result. In addition, these medications often have a sedative effect, which is why they’re sometimes recommended for managing anxiety or sleep disorders.
What are the risks associated with gabapentinoids?
Common side effects associated with gabapentinoids may include:
- Dizziness
- Drowsiness
- Nausea
- Vomiting and/or diarrhoea
- Swollen limbs
- Blurred vision
- Headaches
- Mood changes
- Weight gain
Beyond these side effects, there are other risks linked to gabapentinoids, with some patients becoming addicted. Long-term use of gabapentinoids may result in physical dependence, meaning close monitoring will be required when reducing or withdrawing a dose.
The risk of dependence and adverse side effects increases when gabapentinoids are taken alongside other medications, such as opioids. This can heighten the risk of respiratory depression, which in turn increases the likelihood of respiratory failure or cardiac arrest. Combining gabapentinoids with other medications can impact their effectiveness too, potentially leading to excess doses and other forms of misuse.
Adverse side effects
More severe side effects associated with gabapentinoids can include:
- Thoughts of self-harm or suicide: some patients will experience suicidal thoughts after taking gabapentinoids, so close monitoring is essential
- Hallucinations: in some cases, gabapentinoids have been known to induce hallucinations
- Bruises or bleeding: unexplained bruises can indicate a severe reaction
- Yellowing skin: the eyes or skin may begin to turn yellow in the event of an adverse reaction
- Severe stomach pain or nausea: intense or long-lasting stomach pain or sickness may be a sign of inflammation in the pancreas, and will need addressing urgently
- Allergic reaction: anaphylaxis may occur in patients experiencing an allergic reaction to gabapentinoids, requiring immediate medical attention
In the event of any of these adverse side effects, the gabapentinoid should be withdrawn immediately. The patient will require close monitoring, with appropriate treatment administered.
Gabapentinoids misuse: a growing concern
There are growing concerns surrounding the misuse of gabapentinoids, as these drugs can be addictive, and are often sought-after for non-medical use. Since 2018, gabapentin and pregabalin have been classified as class C drugs in the UK, meaning it’s illegal for patients to possess these without a prescription. This changed the rules surrounding access to gabapentinoids, requiring doctors to sign all prescriptions, and pharmacists to dispense these drugs within 28 days of the prescription.
Despite tighter rules around the prescription of gabapentinoids, 17 million items in this category were prescribed from 2024-25, marking a significant increase from 11 million in the 2015-16 period, data from the NHS Business Services Authority shows. Meanwhile, of the 3,051 deaths in which gabapentinoids were cited as a cause in the UK from 2004 to 2020, 25.3% of these occurred following in patients prescribed both opioids and gabapentinoids.
What’s more, a study published in the International Journal of Drug Policy found that some patients reported using these gabapentinoids to manage pain, distress and insomnia, indicating widespread misuse. There’s a lack of awareness around this issue at present, so more education and monitoring is required to better understand the factors influencing misuse.
Charlotte Saunders, Advanced Specialist Pharmacist in Neurosciences Intensive Care at Oxford University Hospitals NHS Foundation Trust says, “One of the core roles of pharmacists and pharmacy teams is to ensure compliance with national legal standards for prescribing and dispensing of controlled drugs, such as pregabalin and gabapentin. Pharmacists are key to prevention misuse through application of their knowledge and expertise to ensure gabapentinoids are used to manage evidence-based conditions to achieve optimal outcomes for their patients.”
She continues, “Pharmacists are also well placed to collaborate with prescribers and support patients to review and challenge ineffective or unsafe long-term prescribing and explore alternatives, to ensure use is reduced in those patient groups at risk of adverse effects or harm.”
When and how should gabapentinoids be prescribed?
When prescribing gabapentinoids, healthcare professionals must consider:
- Have alternative drugs been tried as a first-line treatment?
- Is there evidence that gabapentinoids will be effective for managing the patient’s condition?
- What other medications is the patient taking? How are gabapentinoids likely to affect this?
- Does the patient have a history of substance abuse, or are they at risk of misuse of dependence?
Healthcare professionals need to make sure patients are aware of the potential risks and side effects associated with a gabapentinoids prescription, and that strict adherence to recommended doses and timings is vital to ensure the medication’s effectiveness.
When should gabapentinoids be avoided?
Gabapentinoids should not be prescribed to patients who:
- Have a known hypersensitivity or allergy to these medications
- Have a history of substance abuse (in cases where there is deemed to be a clinical need for gabapentinoids, close monitoring and short courses should be considered)
- Already have depressed respiratory function
- Are pregnant or breastfeeding
If gabapentinoids are not suitable for a patient, alternative medications and therapies should be explored.
Reducing gabapentinoids: best practice
The reduction, withdrawal or switching of gabapentinoids needs to be a carefully managed process.
For the management of neuropathic pain, gabapentin is typically prescribed for 4 to 6 weeks, but it may be recommended that some patients take it for longer to prevent recurrence. For the treatment of epilepsy, gabapentinoids may be prescribed long-term, initially to get the condition under control, and then to help prevent future seizures.
However, if the use of a particular gabapentinoid is not effective or causes adverse side effects that outweigh its benefits, it may be deemed appropriate to switch from gabapentin to pregabalin or vice versa. This decision should be carefully assessed by the healthcare professional responsible for prescribing.
If it’s decided that the best course of action is to stop gabapentinoid use altogether, this should be done gradually and under close supervision to prevent symptoms of withdrawal.
Expand your knowledge: join the UKCPA Neurosciences Community
Join UKCPA today, and share your insights and experiences into prescribing gabapentinoids. Expand your knowledge with expert-led training, access an extensive peer-submitted resource library, and attend networking events to connect with fellow pharmacists in your field.
Become a member of the UKCPA Neurosciences Community for less than £3 a week, or contact us to find out more.
