Does Cymbalta interact with Lamotrigine? (3+ interactions)

In this article, we will discuss whether Cymbalta interacts with Lamotrigine and what research has to say in this regard. We will also discuss what potential interactions exist between Cymbalta and Lamotrigine and what precautions should be taken when using both medications simultaneously.

Does Cymbalta interact with Lamotrigine?

Yes, Cymbalta interacts with Lamotrigine. Both medications if taken together can interact with each other and cause various side effects. Cymbalta and Lamotrigine belong to different classes and are rarely prescribed together. Due to the risk of interaction, your healthcare may not prescribe this combination unless completely necessary.

Cymbalta (Duloxetine) is a serotonin and norepinephrine reuptake inhibitor (SNRI) used for the treatment of various depressive disorders, fibromyalgia, chronic musculoskeletal pain and diabetic peripheral neuropathic pain (DPNP). Cymbalta works by inhibiting the reuptake of serotonin and norepinephrine in the brain, and as a result, causing its therapeutic effects (1,2). 

Lamotrigine (also known as Lamictal) is an anticonvulsant approved by the FDA for use in the treatment of epilepsy, as adjunctive therapy or monotherapy and also as a maintenance treatment for bipolar I disorder. Although it is not a controlled substance, it does require a prescription (3)

It has been used ‘off-label’ by clinicians for the treatment of acute bipolar depression, unipolar depression, schizophrenia and fibromyalgia. Lamotrigine works by selectively binding to and inhibiting voltage-gated sodium channels. This mechanism decreases abnormal electrical activity (4).

What does research suggest?

Not much research has been conducted on the effects of Cymbalta and Lamotrigine cause when used simultaneously. However, the few studies that have been published show that both medications when used together can cause side effects.

A case study assessing the occurrence of hypomania due to Lamotrigine in a 31-year-old woman stated that the patient experiencing this side effect was on duloxetine when Lamotrigine therapy was started. Initially, the mood of the patient stabilised but two weeks into therapy she began to feel ‘hyper’. The symptoms were reduced once the dose of Lamotrigine was decreased (5).

A study assessing the post-mortem toxicity data of Duloxetine reported that Lamotrigine was found in eight cases during the toxicologic analysis of the fatalities. This suggests that both prescription medicines when used simultaneously can result in fatal side effects (6).

Another case study of a 44-year-old woman reported the emergence of serotonin syndrome (SS) when both medications were used for the management of major depression and polysubstance abuse (7).

How does Cymbalta interact with Lamotrigine?

There are a few interactions that can occur when Cymbalta and Lamotrigine are taken together. These are as follows:

Serotonin syndrome

Cymbalta is a serotonin reuptake inhibitor and some studies suggest that Lamotrigine also causes mild inhibition of serotonin receptors (7,8,9). This effect when combined can increase the levels of serotonin in the brain resulting in the occurrence of serotonin syndrome (SS).

Increased risk of seizures

Cymbalta has a side effect of causing seizures in some patients. As Lamotrigine is a medication used to treat seizures, administering both medications together can decrease the efficacy of Lamotrigine. Treatment with Cymbalta, other SNRIs or SSRIs should not be continued if seizures develop in a patient on Lamotrigine.

Hyponatremia

Hyponatremia is the side effect of SSRI or SNRI therapy. If anticonvulsants are used in individuals on SSRIs or SNRIs, including Duloxetine, the risk of hyponatremia can increase. It can produce symptoms like nausea, vomiting, irritability, and confusion. If you feel any of these symptoms, contact your healthcare provider immediately.

Somnolence and cognitive impairment

Coadministering Lamotrigine and SSRIs or SNRIs, including Cymbalta can increase the side effects of Lamotrigine. These medications can cause an increase in somnolence and cognitive impairment.

What precautions are necessary when combining Cymbalta and Lamotrigine?

Some precautions and recommendations when using Cymbalta with Lamotrigine are as follows:

Consult your healthcare provider

Your healthcare provider will only give you both these medications simultaneously when the benefits outweigh the risks. If you feel that using Cymbalta with Lamotrigine does not suit you, or causes severe side effects, you should consult your healthcare provider. Your doctor will assess your situation and may decrease the dosage of your medications, or suggest an alternative treatment. Do not make amends to your prescription without guidance from a healthcare provider.

Keep track of symptoms

You should keep track of your symptoms. Start logging your symptoms if you feel that they are a periodic occurrence, that occurs at specific times. If they increase to the extent that they get unbearable, you should seek immediate medical advice.

Adapt to a healthier lifestyle

A healthier and more active lifestyle can help you achieve so much that solely medications will never be able to achieve. Taking a balanced diet, doing exercise, and practising relaxation techniques are essential to manage your symptoms.

According to my research, there are potential interactions between Cymbalta and Lamotrigine, and these medications should be used with caution. During the simultaneous use of Cymbalta and Lamotrigine, you look out for seizures, serotonin syndrome and the development of hyponatremia. Consulting a healthcare professional, keeping track of your symptoms and improving your lifestyle can help you manage your medications when coadministered. Open communication with your healthcare provider is recommended so that you may get personalised advice according to your condition.

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