It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to make sure that the combination is safe.
Indigestion remedies (antacids) containing aluminium or magnesium may reduce the absorption of gabapentin from the gut. Indigestion remedies should therefore not be taken at the same time as a dose of gabapentin, or in the two hours before a dose.
It is recommended that people who are taking any antiepileptic medicines should avoid taking the herbal remedy St John’s wort (Hypericum perforatum). This is because St John’s wort may affect the level of antiepileptic medicines in the blood and could increase the risk of seizures.
This medicine is not known to interact significantly with other medicines. However, if it makes you feel sleepy or dizzy, this effect is likely to be increased if you take it in combination with other medicines that can cause drowsiness, in particular morphine, or with alcohol. If you are prescribed morphine in combination with gabapentin you should let your doctor know if it makes you feel sleepy, or if any drowsiness gets worse.
Gabapentin can interact with other medications in several ways, potentially altering their effectiveness or increasing the risk of side effects. Here are some key ways in which gabapentin can affect other medicines:
1. Enhanced Sedative Effects
- Gabapentin can increase the sedative effects of certain central nervous system (CNS) depressants, such as opioids, benzodiazepines, antihistamines, and alcohol. This can lead to enhanced drowsiness, dizziness, respiratory depression, or even overdose in severe cases. It’s particularly important to use caution with opioids, as combining them with gabapentin can increase the risk of respiratory depression.
2. Reduced Absorption with Antacids
- Gabapentin’s absorption can be reduced if taken with certain antacids, particularly those containing aluminum or magnesium (like Maalox or Mylanta). These antacids can reduce gabapentin’s bioavailability by up to 20%. To avoid this, it’s generally recommended to take gabapentin at least two hours after taking an antacid.
3. Interactions with Other Seizure Medications
- If gabapentin is combined with other antiepileptic drugs, it can sometimes increase the side effects associated with these medications. However, it generally doesn’t alter the blood levels of other antiepileptic drugs. Careful monitoring by a healthcare provider is essential if gabapentin is added to a treatment plan for epilepsy to ensure optimal dosing and minimize adverse effects.
4. Increased Risk of CNS Depression with Muscle Relaxants
- Gabapentin can increase the sedative effects of muscle relaxants like cyclobenzaprine or baclofen. This can result in excessive drowsiness, impaired motor function, or respiratory depression. Caution is needed when combining gabapentin with any medication that has a depressant effect on the CNS.
5. Possible Increased Risk of Side Effects with Certain Antidepressants
- Gabapentin may interact with some antidepressants, like amitriptyline and other tricyclics, by intensifying their sedative or anticholinergic effects. Additionally, gabapentin combined with certain antidepressants used for pain management can increase the likelihood of side effects like dizziness, confusion, and fatigue.
6. Blood Pressure Medications
- Gabapentin, while not directly interacting with blood pressure medications, may increase the risk of side effects such as dizziness or fainting when combined with blood pressure-lowering drugs. This is especially true for those that cause similar side effects, as the combined effects may be more pronounced.