What Is Duloxetine (Cymbalta)?
Duloxetine, commonly known under the branded name Cymbalta, is a prescription antidepressant classified as a serotonin-noradrenaline reuptake inhibitor (SNRI) [1, 2]. It has indicated use for several conditions, including depression, anxiety disorders and chronic pain conditions like diabetic neuropathy, fibromyalgia, and musculoskeletal pain [1, 3, 4, 5].
The therapeutic mechanism of duloxetine is to increase the levels of serotonin and norepinephrine, which helps to stabilize mood and modulate pain in the peripheral nervous system [1, 6].
It is not fully clear how duloxetine achieves antidepressant properties, but it is hypothesized it is through increasing the availability of serotonin in the brain. Increased noradrenaline can supplement increases in cognitive function [6]. In pain disorders, increases in serotonin and noradrenaline in the spinal cord can reduce perceived pain by silencing some of the incoming pain signals.
Despite its effectiveness, duloxetine can have side effects, the most common of which include nausea, dry mouth, constipation, and insomnia [7, 8]. In rare cases, side effects can be more severe, such as bleeding gums [8].
Side Effects of Duloxetine
The side effects of duloxetine can be grouped into mild and severe categories.
- Mild Side Effects - The most common mild side effect is nausea, reported in 23.2% of patients. Other mild side effects, such as dry mouth, fatigue, insomnia, constipation, headaches and dizziness, were reported in approximately 10% of cases [9]. Other mild side effects can include excessive sweating, dizziness, reduced appetite, weight loss and bruising [7].
- Severe Side Effects - Severe side effects are less common after taking the prescribed dose of duloxetine. They can include bleeding, eye irritation, fainting, increases in blood pressure, liver damage, mania or hypomania, orthostatic hypotension (fainting when standing up suddenly), rashes, seizures or convulsions, low sodium levels, and in initial stages of treatment, increased risk of suicidal thoughts [8].
Abrupt discontinuation of Duloxetine may result in discontinuation-emergent adverse events, of which dizziness was reported in 12% of patients. Other adverse events included nausea, headache, paresthesia, vomiting, irritability or nightmares, which were reported in less than 6% of patients [10]. Therefore, duloxetine should be discontinued gradually.
What will happen if I drink alcohol while taking duloxetine?
Alcohol is a sedative that increases the release of GABA, an inhibitory neurotransmitter, in the brain. Therefore, it can interact with duloxetine, which increases serotonin and noradrenaline, to interfere with the therapeutic properties of duloxetine [11].
Drinking alcohol while taking duloxetine is generally safe, but there are a few reports of liver damage, especially in patients with a history of liver disease or chronic alcohol use [12, 13, 14]. The liver metabolizes both alcohol and duloxetine. Loading the liver with alcohol can therefore strain the liver's function, increasing the risk of jaundice and yellowing of the skin due to bilirubin accumulation [13, 14]. Nonetheless, these side effects have only been reported sporadically.
What should I do if I drank alcohol while taking duloxetine?
If you have drunk alcohol on one occasion while taking duloxetine, don't panic. There will likely be no detrimental effect on your liver or cognition. It is essential to monitor your symptoms and notice whether you experience any exacerbation of your condition or any unusual symptoms, including nausea, dry mouth, constipation, insomnia, or dizziness and jaundice (yellowing of the skin) in the day/weeks following alcohol consumption. These could be early signs of liver toxicity induced by duloxetine [13]. You should seek medical advice immediately if you notice any of these unusual symptoms.
Most importantly, when drinking alcohol and taking duloxetine, drink sporadically and in moderation.
Interactions of Duloxetine
Duloxetine is known to interact with several other substances. These interactions can affect the drug's therapeutic effects and increase the likelihood of side effects.
- Magnesium Oxide. Magnesium oxide is frequently co-prescribed to offset the constipation effects of duloxetine. Nonetheless, co-administration of magnesium oxide and duloxetine reduces the availability of duloxetine in the blood and reduces duloxetine's antidepressant effects [15].
- Other antidepressants. Duloxetine is generally well tolerated when taken alone, as monotherapy, or when taken in combination with other antidepressants [16].
- Benzodiazepines. Benzodiazepines are a class of sedative drugs commonly used in epilepsy.
- Antibiotics. Certain antibiotics, such as ciprofloxacin, can increase the duration and availability of duloxetine, increasing the risk of side effects and toxicity [11].
- Antipsychotics. There are several reports in which antipsychotic drugs enhanced the antidepressant effects of duloxetine. This would support the use of this combination in treatment-resistant depression. Nonetheless, antipsychotics come with their additional side effects; hence, this combination should be avoided in mild to moderate depression [17].
- Drugs interacting with cytochrome P450. Cytochrome P450 is a common metabolic enzyme critical in breaking down drugs in the liver. Taking other medications that require cytochrome P450 for their breakdown or drugs interfering with cytochrome P450 activity (for example, fluvoxamine) can increase the availability of duloxetine in the bloodstream, increasing the risk of overdose or toxicity [18].
- Monoamine Oxidase Inhibitors. Patients and medical professionals should be cautious that patients taking duloxetine have not taken monoamine oxidase inhibitors in the 2 weeks before starting on duloxetine. This is because inhibition of the monoamine oxidase enzyme reduces the ability of the brain to cope with increased serotonin and norepinephrine and increases the risk of serotonin toxicity [11].
To summarize, drinking alcohol is acceptable when taking duloxetine, as long as it is sporadically and in moderation. It is important to monitor symptoms and seek medical attention if you notice any unusual symptoms.