Dear Editor,
Gabapentin is an anticonvulsant and has been used to manage neuropathic pain. It was originally developed as an antiepileptic agent; however, it is now recommended as a drug of choice for the treatment of neuropathic pain. There is strong evidence that gabapentin is also effective in diabetic neuropathy and postherpetic neuralgia [1].
To the best of our knowledge, macular edema after use of gabapentin has not been reported to date. Therefore, we report a case of macular edema after gabapentin.
A 71-year-old man presented with a 1 day history of visual disturbance and metamorphosis in both eyes. The patient had taken oral gabapentin (Neurontin; Pfizer, New York, NY, USA) and oral methylprednisolone (Methylon; Alvogen, Seoul, Korea) for 8 days for treatment of postherpetic neuralgia. He had no other significant medical history, except hypertension controlled by oral medication. Best-corrected visual acuity (Snellen) was 0.4 (right eye) and 0.2 (left eye), and the intraocular pressure was 9 mmHg (right eye), 11 mmHg (left eye), as determined by non-contact tonometry. Both eyes had moderate cataract. Ophthalmic examination of the anterior segments revealed no other abnormal findings. Dilated fundus examination and spectral domain optical coherence tomography revealed macular edema and serous retinal detachment of macula in both eyes (Fig. 1A-1D). Fluorescence angiography revealed fluorescein dye pooling on the macula and multiple leakages in both eyes (Fig. 1E and 1F). The patient was advised to discontinue gabapentin, and the use of the drug was stopped.
Open in a separate windowAt the initial visit, macular edema and serous detachment on both eyes were observed by fundus photo (A, right eye [OD]; B, left eye [OS]) and spectral domain optical coherence tomography (C, OD; D, OS). On fluorescence angiography, fluorescein dye pooling on the macula and multiple leakages were observed in both eyes (E, OD; F, OS). At 4 weeks after the initial visit, macular edema and serous detachment were much improved on fundus photo (G, OD; H, OS) and spectral domain optical coherence tomography (I, OD; J, OS).
Four weeks after the initial visit, best corrected visual acuity improved to 0.9 (both eye). Fundus exam and spectral domain optical coherence tomography revealed markedly improved macular edema and serous detachment in both eyes (Fig. 1G-1J).
Gabapentin is an amino acid initially designed as a cyclic gamma-aminobutyric acid analogue with action as a gamma-aminobutyric acid agonist [2]. It also acts on different brain receptors by an as-yet unknown mechanism.
Common adverse effects of gabapentin include dizziness, fatigue, drowsiness, sexual dysfunction, weight gain, and peripheral edema [3]. Uncommonly, gabapentin causes blurred vision and diplopia [4]. Steinhoff et al. [5] reported that this drug has been linked with abnormal color perception and reduced contrast sensitivity due to an unknown mechanism. Gabapentin could also cause abnormal finding of visual evoked potentials and pattern electroretinogram [2]. It was suggested that toxic effects on the neuro-transmitter function of the optic nerve might be responsible.
Macular edema on optical coherence tomography after gabapentin has not hitherto been described. Using fluorescence angiography, the present patient was observed to suffer multiple chorioretinitis. Thus, it is possible that the macular edema was due to chorioretinitis. Herpetic infection can also induce chorioretinitis. However, the macular edema in the presented case was spontaneously improved after cessation of gabapentin and steroid, suggesting that chorioretinitis is not a sufficient explanation. Because the precise action mechanism of gabapentin is not known, it is difficult to deduce the mechanism of macular edema after the use of gabapentin. Further studies about the mechanism and frequency of macular edema after gabapentin are required.
In summary, we report macular edema occurring in a male patient receiving gabapentin therapy for postherpetic neuralgia treatment. The macular edema improved after discontinuing the use of the drug. If vision loss after the use of gabapentin occurs, it is prudent to identify macular edema. Gabapentin should be considered one of the potential causes of macular edema.
Footnotes
Conflict of Interest: No potential conflict of interest relevant to this article was reported.
References
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FAQs
Gabapentin could also cause abnormal finding of visual evoked potentials and pattern electroretinogram [2]. It was suggested that toxic effects on the neuro-transmitter function of the optic nerve might be responsible. Macular edema on optical coherence tomography after gabapentin has not hitherto been described.
Does edema from gabapentin go away? ›
We felt that the edema was due to gabapentin and thus discontinued the medication. Within 3 days of discontinuing gabapentin, the edema disappeared. On rechallenge, the edema reappeared within 5 days, and the gabapentin was permanently discontinued with resolution and no recurrence of edema.
What medications cause macular edema? ›
Various agents can cause cystoid macular edema including topical epinephrine, nicotinic acid, topical prostaglandin analogs (e.g., latanoprost), antimicrotubule agents (pacl*taxel, docetaxel), fingolimod, imatinib, glitazones (rosiglitazone, pioglitazone), and trastuzumab.
Does gabapentin mess with your vision? ›
Gabapentin may cause vision changes, clumsiness, unsteadiness, dizziness, drowsiness, sleepiness, or trouble with thinking. Make sure you know how you react to this medicine before you drive, use machines, or do anything else that could be dangerous if you are not alert, well-coordinated, or able to think or see well.
How long does it take for macular edema to go down? ›
The macular edema may take up to a month to approximately four months to go away.
Can gabapentin cause macular edema? ›
If vision loss after the use of gabapentin occurs, it is prudent to identify macular edema. Gabapentin should be considered one of the potential causes of macular edema.
What is the biggest side effect of gabapentin? ›
It can also cause diarrhea. More serious (but rare) side effects include suicidal thoughts or behavior, and mood changes in children. Combining gabapentin with certain medications, like opioids or benzodiazepines, can also lead to difficulty breathing and overdose in rare cases.
Is macular edema reversible? ›
Macular edema cannot be cured but can be treated effectively if diagnosed early. Vision can be better preserved with early treatment of macular edema and the underlying condition causing it.
How do you stop macular edema? ›
Medicines called anti-VEGF drugs can slow down or reverse macular edema. Medicines called steroids can also help with swelling in the retina. Your doctor will usually inject these medicines into — or very close to — your eye.
Can macular edema resolve itself? ›
Rarely, macular edema will go away on its own. However, if you have symptoms of macular edema, it's important that you see an ophthalmologist right away. If left untreated, macular edema can cause severe vision loss and even blindness. There are several treatment options available for macular edema.
Gabapentin and pregabalin are used to treat a variety of neurologic conditions including seizures, nerve pain, and restless legs syndrome. The new warning concerns the risk of potentially fatal respiratory depression with this class of drugs.
What is the dark side of gabapentin? ›
Very few people taking gabapentin have serious problems. Call a doctor or call 111 straight away if you have a serious side effect, including: thoughts of harming or killing yourself – a small number of people taking gabapentin have had suicidal thoughts, which can happen after only a week of treatment.
What happens if you take gabapentin every day? ›
Gabapentin is known to cause respiratory depression, particularly when combined with other central nervous system depressants. Long-term use can cause physiologic dependence and withdrawal syndrome on cessation, characterized by diaphoresis, anxiety, confusion and, rarely, seizures.
What is the new treatment for macular edema? ›
Vabysmo (faricimab), approved in February 2022, is the first drug to target two disease pathways that cause DME, rather than just a single pathway.
What is the most common cause of macular edema? ›
In the retina, blisters of fluid form and swell the retina—this is macular edema. Factors likely to cause macular edema include conditions that: Cause more fluid to leak from blood vessels (diabetes and high blood pressure) Increase inflammation in the eye (surgery, inflammatory diseases)
Can vision be restored after macular edema? ›
A treatment for macular edema due to retinal vein occlusion yielded vision gains for at least five years, although many patients required ongoing treatment. The study shows that macular edema from retinal vein occlusion can be successfully treated with continued monitoring and individualized therapy.
How long does it take for edema swelling to go down? ›
Swelling normally lasts for a few days. In the first two days, you will experience the most swelling, and it should start to reduce by the third day. Following treatment from your healthcare provider reduces the amount of swelling you might experience.
Does gabapentin make you retain fluid? ›
Gabapentin (Neurontin, Horizant, Gralise) is a medication used to treat nerve pain from shingles, seizures, and restless legs syndrome. Some people taking it report fluid retention and swelling in their extremities. Swelling may be more likely if you're older, or if you're taking a higher gabapentin dosage.
Can edema swelling reversed? ›
Edema cannot be “cured.” The only way to treat edema is to treat the condition that is causing it. But there are some things you can do to keep the swelling down. Put a pillow under your legs when you are lying down. Wear support stockings, which you can buy at most drugstores.
How do you get rid of edema medication? ›
Diuretics — Diuretics are a type of medication that causes the kidneys to excrete more water and sodium, which can reduce edema. Diuretics must be used with care because removing too much fluid too quickly can lower the blood pressure, cause lightheadedness or fainting, and impair kidney function.
