Difference between gabapentin and pregabalin

A lot of people get confused about the difference between gabapentin and pregabalin and always ask about how to differentiate between them. We will discuss this in more detail here.

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2020-07-01 06:22

Pregabalin and gabapentin are two drugs from the same family, they are antiepileptic medications, and both are used for treating neuropathic pain associated with spinal cord injury, herpes zoster. There are similar in several side effects like Drowsiness, Dizziness, Vision problems, Tremors, Loss of balance or coordination, but gabapentin can cause more side effects other than those with pregabalin like:

  • Difficulty speaking
  • Jerky movements
  • Viral infections
  • unusual eye movements
  • Fever

pregabalin can cause side effects that gabapentin cannot do it like:

  • Constipation
  • Swelling (edema)
  • Dry mouth
  • Weight gain
  • Breast enlargement


Both drugs can interact with the same drugs that cause CNS (central nervous system) sedation including opioids and alcohol.  Gabapentin may also interact with other drugs used for pain like nonsteroidal anti-inflammatory drugs (NSAIDs).




How do they work?

There is no difference between gabapentin and pregabalin in the mechanism of action of both drugs, they are similar in structure to the inhibitory neurotransmitter gamma-aminobutyric GABA, they are binding to GABA receptors and starting a cascade of reactions that result in anticonvulsant and analgesic effects.


What are the differences in the indications of pregabalin and gabapentin?

Pregabalin is used for:

  • Treating fibromyalgia
  • Neuropathic pain associated with diabetic peripheral neuropathy or herpes
  • Spinal cord injury
  • treating partial-onset seizures in adults as adjunctive therapy


Gabapentin can be used for different indications other than pregabalin; there are many non-FDA-approved uses for gabapentin. These include:

  • Alcohol withdrawal
  • Cocaine withdrawal
  • Hiccups
  • Restless leg syndrome
  • Hyperhidrosis
  • Headaches
  • Diabetic neuropathy
  • Hot flashes
  • Fibromyalgia


What are the side effects of pregabalin and gabapentin?

All the antiepileptics include pregabalin and gabapentin increase the risk of suicidal thinking so doctors always weigh the benefits against this risk.

The most noticed side effect associate with pregabalin:

  • double vision (diplopia)
  • drowsiness
  • dizziness
  • dry mouth (xerostomia)
  • edema (accumulation of fluid)
  • fatigue (tiredness)
  • blurred vision
  • difficulty concentrating
  • weight gain
  • abnormal gait (ataxia)
  • tremor

Other uncommon side effects include:

  • heart failure
  • constipation
  • increased appetite
  • nausea
  • reduced blood platelet counts
  • increased blood creatinine kinase levels.
  • amnesia
  • flatulence
  • disorientation
  • Myoclonus (involuntary movement).
  • low blood pressure
  • vomiting


which is defined as severe muscle injury reported with the use of pregabalin and Increased creatinine kinase in the blood is considered a remarkable sign for it.

The most common side effects of gabapentin are similar to that of pregabalin, other adverse effects and serious side effects related to gabapentin only are:

  • Weight gain
  • Joint pain
  • Motion sickness
  • Blurred vision
  • Viral infection


Withdrawal symptoms of pregabalin and gabapentin

Both of them are not opioid narcotic but they have not controlled substances but abrupt discontinuation of them results in withdrawal symptoms which are slightly different from each other

Withdrawal symptoms associated with pregabalin:

  • Headaches
  • Anxiety
  • Agitation
  • Sweating
  • Rapid heartbeat or palpitations
  • Seizures
  • Difficulty falling or staying asleep
  • Behavioral changes
  • Mood changes
  • Depression
  • Suicidal thoughts or behavior.
  • Nausea
  • Diarrhea

Withdrawal symptoms associated with gabapentin:

  • Sweating
  • Goosebumps (piloerection)
  • Muscle pain
  • Insomnia
  • Anxiety

The dosage of gabapentin and pregabalin

Pregabalin is usually available in dosage forms of 50, 150, 300 mg tablets or oral solution. Usually, the dose started with 50 mg twice or three times daily and increased to reach a maximum dose of 300mg to 600mg daily according to indication. It Is recommended to take an extended dosage form after the evening meal.

Gabapentin is available in 300mg, 400mg, 600mg, 800mg tablets, and may be taken with or without food. The dosage usually ranges from 300 three times daily to 600mg three times daily according to the indication.

Drug interactions of gabapentin and pregabalin

Pregabalin interacts with drugs that cause CNS depression-like opioids and alcohol. Pioglitazone and rosiglitazone also react with pregabalin causing weight gain, fluid retention, and possibly heart failure. Therefore, combining pregabalin with these drugs may increase the occurrence of weight gain and fluid retention.

One of the most significant drug interactions with gabapentin is that antacids can reduce gabapentin concentration in blood so they must be separated by at least 2 hours. Morphine is also increasing blood concentrations of gabapentin and therefore increases the depressant effect of gabapentin.

Pregnancy and breastfeeding

Pregabalin crosses the placenta and No available data till now support pregabalin use in pregnancy, and also presented in breast milk, it is not recommended to be used with breastfeeding unless the benefits outweigh the risks.

Gabapentin is categorized as C for use in pregnancy (no evidence of risk of the fetus has not been detected), and it is recommended to use folic acid before pregnancy in women who use gabapentin.

Gabapentin is presented in breast milk by a significant amount, so it is recommended to avoid use unless the benefits outweigh the risks for the fetus.

We hope that this topic helped you to understand the difference between gabapentin and pregabalin.

The difference between gabapentin and pregabalin is clear now, correct?