Gabapentin: what is it for and how does it work?

[Josephine]

Gabapentin is not an analgesic (pain killer). It is a medication used to treat epilepsy, neuropathic pain, hot flashes, and restless legs syndrome. In epilepsy it may be used for those with partial seizures.

Gabapentin works in your brain and nervous system. It stabilises the electrical activity in your brain, and affects the way your nerves send messages to your brain. The exact way in which gabapentin works is not fully understood.

Gabapentin appears to affect the build up of electrical signals in the nerve cells, as well as affecting the activity of various neurotransmitters in the brain and nervous system. Neurotransmitters are natural body chemicals that are involved in transmitting messages between nerve cells. GABA is a neurotransmitter that acts as a natural 'nerve-calming' agent. It helps keep the nerve activity in the brain in balance. Gabapentin appears to increase production of GABA.

Glutamate is a neurotransmitter that acts as a natural 'nerve-exciting' agent. It's released when electrical signals build up in nerve cells and subsequently excites more nerve cells. It is thought to play a key role in causing epileptic seizures and transmitting pain signals to the brain. Gabapentin appears to reduce the release of glutamate.

This information was obtained from NetDoctor

Another similar drug is pregabalin, marketed as Lyrica. Gabapentin and pregabalin are different drugs but they rather like cousins. Lyrica has one less carbon atom in the molecule. This makes the structure more open. It is absorbed more quickly and lasts longer than gabapentin.

However, they both work much the same way by attaching themselves to a specific sub-unit protein and thereby buffer the calcium ions in the voltage gated calcium channels. This is where nerves are activated. This results in the chemically excited nerves being calmed down.

 

[Josephine]

Generally you get started on a smallish dose, about 100mg once or twice a day. If that hasn't given you relief within the next 3-4 days, contact your GP/doctor again as you will need the dose increased. It can actually be increased to as much as 3,600mg three times a day so don't worry about it.

I was on 300mg twice a day for about 3 months and then reduced in the manner shown in the chart below. I suggest you copy this and keep it by for your future reference.

The side effects are many but note the frequency as listed as more often than they do not put in an appearance!

For the Consumer
Applies to gabapentin: oral capsule, oral solution, oral suspension, oral tablet

In addition to its needed effects, some unwanted effects may be caused by gabapentin. In the event that any of these side effects do occur, they may require medical attention.

Severity: Minor
Some of the side effects that can occur with gabapentin may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

More common:

• Blurred vision
• cold or flu-like symptoms
• delusions
• dementia
• hoarseness
• lack or loss of strength
• lower back or side pain
• swelling of the hands, feet, or lower legs
• trembling or shaking

Less common or RARE:

• Accidental injury
• appetite increased
• back pain
• bloated or full feeling
• body aches or pain
• burning, dry, or itching eyes
• change in vision
• change in walking and balance
• clumsiness or unsteadiness
• congestion
• constipation
• cough producing mucus
• decrease in sexual desire or ability
• difficulty with breathing
• dryness of the mouth or throat
• earache
• excess air or gas in the stomach or intestines
• excessive tearing
• eye discharge
• feeling faint, dizzy, or lightheadedness
• feeling of warmth or heat
• flushed, dry skin
• flushing or redness of the skin, especially on the face and neck
• frequent urination
• fruit-like breath odor
• impaired vision
• lack of co-ordination
• increased hunger
• increased sensitivity to pain
• increased sensitivity to touch
• increased thirst
• indigestion
• noise in the ears
• pain, redness, rash, swelling, or bleeding where the skin is rubbed off
• passing gas
• redness or swelling in the ear
• redness, pain, swelling of the eye, eyelid, or inner lining of the eyelid
• runny nose
• sneezing
• sweating
• tender, swollen glands in the neck
• tightness in the chest
• tingling in the hands and feet
• trouble sleeping
• trouble swallowing
• trouble thinking
• twitching
• unexplained weight loss
• voice changes
• vomiting
• weakness or loss of strength
• weight gain