Gabapentin and alcohol: what you should know

Gabapentin and alcohol both act on the central nervous system (CNS), which is your brain and spinal cord. When you take them together, their effects add up or even multiply.

The BNF and NHS advise you to be careful with alcohol, or to avoid it, while you take gabapentin.

Key reasons to avoid the combination:

• More drowsiness: both make you sleepy. Together they can make you very drowsy, so it is hard to function safely
• More dizziness: the risk of falls and injuries goes up a lot, above all in older adults
• Poor coordination and judgement: your movement and your thinking are hit harder than with either one alone
• Slowed breathing: together, and at higher doses, your breathing can become dangerously slow
• Worse thinking: your memory, focus and reaction times can be badly affected

The MHRA has warned that gabapentinoids, which include gabapentin, are risky when mixed with other CNS depressants such as alcohol.

This is one reason gabapentin became a controlled substance in the UK.

It helps to know how the two drugs interact. That explains why the mix is risky.

How the body absorbs the drugs:

Your body takes up gabapentin in the small intestine through a transport system that can become full. Alcohol can change how fast your gut moves and how much blood flows to it.

This may affect how much gabapentin you absorb, in ways that are hard to predict.

How the drugs act on the brain:

The more important effect is on the brain. Both gabapentin and alcohol boost the brain's calming signals:

• Gabapentin attaches to the alpha-2-delta part of voltage-gated calcium channels. This lowers the release of chemicals that excite nerve cells
• Alcohol boosts the GABA-A receptor and blocks the NMDA glutamate receptor
• Together, they slow the CNS more than either one on its own

So even a small amount of alcohol can have a strong effect when you also take gabapentin.

A glass of wine that would normally relax you a little could instead leave you very drowsy, unsteady or confused.

It differs from person to person:

How strong the interaction is varies between people.

It depends on your gabapentin dose, how much alcohol you drink, your body weight, your age, how well your kidneys work and any other medicines you take.

This mix does more than make you sleepy. It can cause serious medical problems.

Higher fall risk:

Both drugs cause dizziness and poor balance. Together they raise your risk of a fall. This matters most for older patients, who may break a bone or hurt their head.

Slowed breathing:

Gabapentin and alcohol can both slow your breathing. Together, your breathing may become dangerously slow or shallow, above all while you sleep.

The risk is higher if you already have a breathing problem such as COPD or obstructive sleep apnoea.

Overdose risk:

Alcohol makes it easier to reach a toxic level of gabapentin. Signs of a gabapentin overdose include heavy drowsiness, slurred speech and double vision. In severe cases, the person passes out.

Seizure risk:

If you take gabapentin for epilepsy, alcohol can make seizures more likely and may trigger one. Stopping alcohol after heavy use is also a well-known cause of seizures.

Mental health effects:

Alcohol is a depressant and can make mood problems worse. Gabapentin can also affect mood and the mind. Together, the mix may worsen depression, anxiety or suicidal thoughts.

The safest choice is to avoid alcohol fully while you take gabapentin. If you do decide to drink, the advice below may lower the risk.

NHS and BNF advice:

• The BNF says alcohol may make the side effects of gabapentin worse
• The NHS patient information for gabapentin says to avoid alcohol, or cut down a lot
• Your prescriber should talk to you about alcohol when you start gabapentin

If you do drink:

• Start with a very small amount. See how you feel before you have more
• Never drive or use machinery if you have had any alcohol while on gabapentin
• Avoid spirits. Stick to drinks with less alcohol if you must drink
• Leave as much time as you can between your gabapentin dose and any alcohol
• Have someone with you who can keep an eye on you
• Take extra care if you also take opioids, benzodiazepines or other sedating medicines

For patients with alcohol use disorder:

Sometimes doctors prescribe gabapentin off-label to help with alcohol withdrawal or to reduce cravings. If you take it for this reason, you should be under close medical care and not drinking.

Tell your treating team honestly about any slip-ups.

If you or someone else has mixed gabapentin and alcohol and shows any of these signs, get medical help right away:

• Extreme drowsiness or being unable to stay awake
• Slow, shallow or uneven breathing
• A bluish colour to the lips or fingertips (cyanosis)
• Confusion that is more than you would expect from being a bit drunk
• Passing out or being unable to wake up
• Seizures
• Being sick while drowsy (the vomit could enter the lungs)

Call 999 right away if someone is unresponsive or their breathing looks affected.

While you wait for the ambulance, put the person on their side (the recovery position) to keep their airway clear. Do not leave them alone.

If you are worried about your drinking, or find it hard to avoid alcohol while on gabapentin, talk to your GP. You can get help through NHS alcohol services.

Your prescriber may also suggest other treatments that are safer with alcohol.