Gabapentin and alcohol: what you should know

Both gabapentin and alcohol act on the central nervous system (CNS), and their combined effects are additive or even synergistic.

The BNF and NHS advise caution or avoidance of alcohol during gabapentin treatment.

Key reasons to avoid the combination:

• Increased sedation: both substances cause drowsiness, and together they can produce profound sedation that impairs your ability to function safely
• Enhanced dizziness: the risk of falls and injuries increases significantly, particularly in older adults
• Impaired coordination and judgement: motor skills and decision-making are more severely affected than with either substance alone
• Respiratory depression: in combination, especially at higher doses, there is a risk of dangerously slowed breathing
• Worsened cognitive function: memory, concentration and reaction times may be severely impaired

The MHRA has highlighted that gabapentinoids (including gabapentin) carry particular risks when combined with other CNS depressants, including alcohol.

This is one of the reasons gabapentin was reclassified as a controlled substance in the UK.

Understanding the pharmacological interaction helps explain why the combination is risky.

Pharmacokinetic considerations:

Gabapentin is absorbed in the small intestine via a saturable transport mechanism. Alcohol can alter gut motility and blood flow, potentially affecting gabapentin absorption in unpredictable ways.

Pharmacodynamic interaction:

The more important interaction is pharmacodynamic. Both gabapentin and alcohol enhance inhibitory signalling in the brain:

• Gabapentin binds to the alpha-2-delta subunit of voltage-gated calcium channels, reducing excitatory neurotransmitter release
• Alcohol enhances GABA-A receptor activity and inhibits NMDA glutamate receptors
• Together, they produce a greater degree of CNS depression than either substance alone

This means that even moderate amounts of alcohol may produce disproportionately strong effects when combined with gabapentin.

A glass of wine that might normally cause mild relaxation could lead to marked drowsiness, unsteadiness or confusion.

Individual variation:

The degree of interaction varies between individuals and depends on gabapentin dose, the amount of alcohol consumed, body weight, age, kidney function and whether other medications are being taken.

The risks of this combination extend beyond simple drowsiness and can have serious clinical consequences.

Increased fall risk:

Dizziness and impaired balance from both substances together significantly raise the risk of falls. This is especially concerning for older patients, who may sustain fractures or head injuries.

Respiratory depression:

Both gabapentin and alcohol can suppress breathing. Combined, they may cause breathing to become dangerously slow or shallow, particularly during sleep.

This risk is heightened in people with pre-existing respiratory conditions such as COPD or obstructive sleep apnoea.

Overdose risk:

Alcohol lowers the threshold for gabapentin toxicity. Signs of gabapentin overdose include marked drowsiness, slurred speech, double vision and in severe cases, loss of consciousness.

Seizure risk:

For patients taking gabapentin for epilepsy, alcohol consumption can lower the seizure threshold, potentially triggering breakthrough seizures.

Alcohol withdrawal is itself a well-known cause of seizures.

Mental health effects:

Alcohol is a depressant and can worsen mood disorders. Combined with gabapentin's potential neuropsychiatric effects, the combination may exacerbate depression, anxiety or suicidal thoughts.

The safest approach is to avoid alcohol entirely while taking gabapentin. However, if you do choose to drink, the following guidance may help reduce risk.

NHS and BNF recommendations:

• The BNF advises that alcohol may enhance the adverse effects of gabapentin
• The NHS patient information for gabapentin recommends avoiding alcohol or limiting intake significantly
• Your prescriber should discuss alcohol use with you when starting gabapentin

If you do drink:

• Start with a very small amount and observe how you feel before having more
• Never drive or operate machinery if you have consumed any alcohol while on gabapentin
• Avoid spirits and stick to lower-alcohol options if you must drink
• Space your gabapentin dose and alcohol consumption as far apart as possible
• Have someone with you who can monitor you
• Be especially cautious if you are also taking opioids, benzodiazepines or other sedating medicines

For patients with alcohol use disorder:

Gabapentin is sometimes prescribed off-label to support alcohol withdrawal or reduce cravings.

If you are taking gabapentin for this purpose, you should be under close medical supervision and abstaining from alcohol. Discuss any lapses honestly with your treating team.

If you or someone else has combined gabapentin and alcohol and experiences any of the following, seek medical help immediately:

• Extreme drowsiness or inability to stay awake
• Slow, shallow or irregular breathing
• Bluish tinge to the lips or fingertips (cyanosis)
• Confusion or disorientation beyond what you would expect from mild intoxication
• Loss of consciousness or inability to be roused
• Seizures
• Vomiting while drowsy (risk of aspiration)

Call 999 immediately if someone is unresponsive or their breathing appears compromised.

While waiting for the ambulance, place the person in the recovery position (on their side) to protect the airway. Do not leave them unattended.

If you are concerned about your alcohol use or finding it difficult to avoid drinking while on gabapentin, speak to your GP.

Support is available through NHS alcohol services, and your prescriber may be able to suggest alternative treatments that carry less risk with alcohol.