Can Topamax and Effexor be taken together? (+1 uses)

In this article, we will discuss if you can take Topamax with Effexor. Topamax (topiramate) is used in the treatment and management of seizures. Effexor (venlafaxine) is a selective serotonin-norepinephrine reuptake inhibitor (SNRI) that is used in the treatment of generalized anxiety disorder, panic disorder, and anxiety.

Can Topamax and Effexor be taken together?

Yes, Topamax and Effexor can be taken together. However, you need to monitor any abnormal symptoms during the concomitant use of the two drugs. Topamax and Effexor are reported to have moderate drug interaction.

Effexor can occasionally result in hyponatremia, a condition where blood salt levels drop too low. Using Effexor with Topamax can make this risk higher. Furthermore, in some individuals, Effexor might also induce seizures, which may lessen the efficacy of Topamax which is used to manage seizures.

If you observe signs of discomfort, nausea, or mood alteration, consult your physician immediately. If the drug interaction is severe, your physician might want to recommend alternatives that do not interact with one another. Sometimes a dose adjustment would be sufficient to lower the chances of side effects.

Under what circumstances can Topamax and Effexor be used together?

Under certain conditions, Topamax and Effexor can be given concomitantly, however, careful monitoring is required. Topamax and Effexor have been used to treat various illnesses together, including epilepsy, and migraine with depression.

The mode of action of Topamax and Effexor are fundamentally different: Topamax predominantly affects GABA receptors and voltage-gated sodium channels, whereas Effexor reduces the uptake of serotonin and norepinephrine from the synaptic cleft.

In one of the case studies, a female patient diagnosed with posterior cerebral artery infarction experienced visual hallucinations while taking Effexor. Topamax (125 mg) was added to the treatment regimen. After taking Topamax daily, she stopped having hallucinations and experienced slight weight loss (1).

In yet another case, Topamax was used for Effexor-induced night-eating syndrome (NES). A 54-year-old woman had been experiencing weight gain and nocturnal eating during the use of Effexor. Topamax was initiated at a dose of 25 mg/day in the evening.

The patient reported improvement in eating habits following a 6-week course of therapy at a dose of 75 mg/day. She reported a noticeable decrease in the need to eat at night or in the evening (2).

What circumstances restrict the use of Topamax and Effexor together?

The concomitant use of Topamax with Effexor is restricted in patients with severe cases of epilepsy and seizures. The concomitant use should also be avoided in case of hyponatremia caused by Effexor as a side effect. 

In a case report, a 40-year-old lady reported delusional thinking and multiple attempts at self-harm About a week before the strange behaviour began, the patient was put on Topamax for weight loss along with Effexor. The patient had no previous symptoms of psychosis or behavioural problems. After receiving lurasidone, the patient’s psychosis resolved (3).

In another case report, superaciliary effusions were observed in a patient taking Topamax and Effexor together. This resulted in secondary angle closure glaucoma. However, the authors attributed the glaucoma and effusions to the use of Topamax (4).

What are the potential side effects of taking Topamax with Effexor?

Seek immediate medical help if the patient has any of the following symptoms while taking Topamax with Effexor:

• nausea and vomiting,
• headache,
• difficulty concentrating,
• disorientation,
• muscle spasm,
• memory loss,
• lethargy,
• reaction speed,
• seizures, and
• fainting.

How to manage side effects caused by Topamax with Effexor?

Effexor should be used with caution in patients who have unstable epilepsy. The following interventions should be taken to reduce the side effects caused by concomitant administration of Topamax with Effexor:

• Adjust the dose of Effexor while giving Topamax.
• If the frequency of seizures rises, the administration of Effexor should be tapered off. Abruptly discontinuing Effexor can cause withdrawal symptoms.
• Monitor the sodium level of the patient periodically.
• Isotonic saline or water can be given to promptly restore sodium levels in patients exhibiting rapid hyponatremia without causing cerebral oedema.
• Oral or enteral-free water should be given whenever feasible to restore the body’s natural water balance (5). 

Which medicines cannot be taken with Topamax?

The following drugs can have a potential drug interaction with Topamax and hence should be used with caution.

• Antidepressants: Drugs similar to SNRIs, like selective serotonin reuptake inhibitors (SSRIs), should not be given with Topamax.
• Antidiabetic drugs: drugs used to lower blood sugar levels like metformin and glibenclamide. 
• Blood pressure medicines: medicines used to treat high blood pressure like diltiazam and propanalol. 
• Antipsychotic agents: drugs used to treat psychosis like risperidone.

Which medicines cannot be taken with Effexor?

The following drugs should not be coadministered with Effexor as they might cause severe side effects.

• Other antidepressants: monoamine oxidase inhibitors like selegiline and rasagiline should not be administered with Effexor. 
• Serotogenic drugs: medicines that increase the serotonin level like lithium and S. John warts. 
• Blood thinners: anticoagulants and antiplatelets like warfarin, and clopidogrel.
• Nonsteroidal antiinflammatory drugs: NSAIDs like aspirin and naproxen.
• What are the precautions while taking Topamax with Effexor?

I always read the literature provided with medication as a trusted source to identify potential drug interactions. There might be coloured stickers on the label that describe the interaction.

If the literature is missing, ask your pharmacist to print one for you. It is important to ask your doctor or pharmacist about the possible drug interaction in case of ambiguities. 

References