Short-term harms of gabapentin
These harms appear within hours of taking it, and become clearer with amounts larger than prescribed:
- Dizziness and drowsiness, the most common side effects.
- Unsteadiness and poor balance and motor coordination.
- Double or blurred vision and slurred speech with large amounts.
- Tiredness, sluggishness and slow thinking.
- Nausea and diarrhea in some people.
Why is mixing gabapentin with opioids dangerous?
In December 2019, the US Food and Drug Administration warned that gabapentin and pregabalin can cause serious breathing problems in people with risk factors, chief among them taking opioids, sedatives or alcohol with them. Medical references describe cases of suppressed breathing and severe drowsiness, some of them fatal, when gabapentin was combined with opioids.
- Mixing it with tramadol, tapentadol, heroin or other opioids.
- Mixing it with benzodiazepines such as Xanax and Rivotril.
- Drinking alcohol while using it.
- Chronic lung disease and older age.
- Reduced kidney function, which raises its concentration in the blood.
Long-term harms of gabapentin
| System | Possible harms |
|---|---|
| Nervous system | Persistent drowsiness and dizziness, poor concentration and memory, and physical dependence with non-medical use. |
| Kidneys | The drug leaves the body unchanged through the kidneys, so weak kidneys raise its concentration and the risk of toxicity. |
| Muscles and movement | Unsteadiness and poor balance raise the risk of falls and fractures, especially in older adults. |
| Weight and body | Weight gain and swelling of the limbs in some patients. |
| Immune system and skin | Rarely, a severe multi-organ allergic reaction that appears with fever, rash and swollen glands, or sudden swelling of the face and throat. |
Harms of gabapentin to mental health
- Mood swings and irritability, especially with irregular use.
- Depression or loss of enjoyment of ordinary things in some patients.
- An increased risk of suicidal thoughts, a general warning for epilepsy medications that calls for watching for any sudden change in mood.
- In children taking it for epilepsy, irritability and emotional swings may appear, and the doctor should be told about them.
If the person has an earlier psychiatric disorder, care is needed that deals with both conditions together, known as dual diagnosis.
Does gabapentin affect driving?
Yes. The official leaflet states that gabapentin can cause marked impairment of the ability to drive, and that the patient may not feel it themselves. For this reason, it is advised not to drive or operate machinery until the patient knows how the medication affects them, and the risk rises greatly with large amounts or mixing with other substances.
Harms of mixing gabapentin with other substances
| The mix | The main risk |
|---|---|
| Gabapentin + opioids | Doubled suppression of breathing and consciousness, which can be fatal. |
| Gabapentin + sedatives | Deep drowsiness and severe suppression of breathing. |
| Gabapentin + alcohol | Doubled suppression of breathing, with a risk of falls and choking on vomit. |
| Gabapentin + pregabalin | The same class of drug, so the side effects multiply with no benefit. |
| Gabapentin + hashish | More dizziness, unsteadiness and poor concentration. |
Harms of gabapentin in pregnancy
Medical references note that exposure to gabapentin in late pregnancy has been linked to a higher risk of a smaller baby, preterm birth and admission of the newborn to intensive care. But stopping suddenly can also be dangerous, especially for a woman with epilepsy. For this reason, a pregnant woman should see her doctor right away to balance benefit and risk and make a safe plan for her and the baby.
Harms of gabapentin in older adults and people with kidney disease
Older adults and people with kidney disease are more sensitive to the harms of gabapentin, because the kidneys clear it slowly and it builds up in the body. Their main risks include dizziness, falls and fractures, confusion, severe drowsiness, and suppressed breathing with other medications. For this reason the doctor adjusts the plan to kidney function and follows them closely.
What happens when a large amount of gabapentin is taken on its own?
The official leaflet notes that cases of very large amounts of gabapentin taken alone showed double vision, slurred speech, drowsiness, lethargy and diarrhea. Although gabapentin alone is rarely fatal in a healthy person, any poisoning calls for medical assessment, because the person who took it has often taken other substances with it without saying so.
Harms of gabapentin in teenagers and young people
The teenage brain is more sensitive to any psychoactive substance, and young people are more likely to try dangerous mixtures without realizing the consequences. A scientific review published in 2026 noted a growing trend of gabapentinoid misuse among teenagers, in the Middle East and North Africa region in particular. Early conversation within the family, and keeping nerve medications out of children's reach, are among the simplest and strongest forms of prevention.
Do the harms of gabapentin go away after stopping?
Most harms improve after gradual withdrawal under medical supervision: balance and concentration return, drowsiness eases, and mood improves. The important thing is that stopping is not sudden, and that any accompanying dependence on opioids or sedatives is treated at the same time.
Signs of gabapentin poisoning or overdose: call an ambulance (123) immediately
- Extreme drowsiness, or difficulty waking the person, with no response to calling
- Slow, shallow or irregular breathing, especially if the medicine was mixed with tramadol, opioids, sedatives or alcohol
- Blue or pale lips and fingernails
- Very slurred speech, or double vision with severe unsteadiness and inability to stand
- Sudden swelling of the face, lips and throat with difficulty swallowing or breathing
Call an ambulance at 123 immediately, place the person on their side so they do not choke, give them nothing by mouth, stay with them until help arrives, and keep the medicine packs they took to show the doctor. If opioids are part of the mixture, the emergency team may use naloxone to reverse their effect.
Call the ambulance 123
23Social harms