Fluoxetine Overview
Fluoxetine, most commonly known under its brand name Prozac, is a prescription Selective Serotonin Reuptake Inhibitor (SSRI) [1]. Fluoxetine can be used to treat a variety of mental health conditions, including depression, obsessive-compulsive disorder, bulimia nervosa, and anxiety/panic attacks [1].
Fluoxetine increases serotonergic neurotransmission by inhibiting serotonin reuptake into the primary neuron from which serotonin was initially released. This increases the availability of serotonin in the synapse, increasing the activation of serotonergic receptors on the secondary (receiving) neuron [2].
The daily dose of fluoxetine ranges from 20-60mg, most commonly taken in capsules. The half-life of fluoxetine is up to 2 weeks, which is why symptom relief can take several weeks to become apparent. Efficacy-wise, fluoxetine has comparable effects to other antidepressants such as imipramine, amitriptyline, and doxepin [2].
Common side effects experienced while taking fluoxetine include nausea, anxiety, insomnia, and headache. However, unlike other types of antidepressants, the side effects of fluoxetine and risk of overdose are significantly lower and fluoxetine is thus well tolerated across patient groups [2, 3, 4].
Side Effects of Fluoxetine
- Nausea, nervousness, and insomnia are the most common side effects, and they are more frequently reported with fluoxetine compared to tricyclic antidepressants [3]. Overdose with fluoxetine has also been reported in a extremely limited number of cases, making fluoxetine one of the safest antidepressants [4].
Mild Side Effects of Fluoxetine
- Headaches
- Diarrhea
- Dry mouth
- Increased anxiety
- Fatigue
- Indigestion
- Loss of appetite
- Hot flashes
- Sexual side effects
- Vomiting
- Sweating more than usual
Moderate to Severe Side Effects of Fluoxetine
More severe side effects of fluoxetine are less common. Still, they can include sleep difficulties, abnormal or heavy bleeding, low sodium levels, serotonin syndrome (abnormal buildup of serotonin in the nervous system), long QT syndrome (an abnormality in heart rate rhythms), increased suicidality [6, 5].
It is helpful to consult with your medical practitioner if you experience any of these side effects, as the professional can tailor the medication and dose to minimize side effects.
Can I Drink Alcohol While Taking Fluoxetine?
Alcohol and fluoxetine are both psychoactive substances that impact mood and alertness. Alcohol is a sedative that increases the GABA-ergic neurotransmission in the brain and reduces inhibition, cognitive ability and motor coordination.
Alcohol counteracts the mood improvements experienced under fluoxetine, even if the drugs are taken 12 hours apart. Individuals taking fluoxetine are at a higher risk of feeling depressed, suicidal and have trouble with cognitive functioning while drinking alcohol. Furthermore, fluoxetine can enhance alcohol's sedative properties, making you drowsy, fatigued and more prone to injury [7].
On the other hand, studies have shown that fluoxetine can decrease alcohol intake in individuals with moderate alcohol dependence [8]. This demonstrates the tendency of alcohol to be used as a mood-booster in specific individuals, which is ameliorated when low mood is medicated by fluoxetine. However, this may not be the case in all alcohol-dependent individuals [9].
To summarize, there are no severe risks of drinking alcohol when taking fluoxetine. Nonetheless, individuals will likely benefit from not drinking alcohol while taking fluoxetine due to the detrimental effects on mood and cognition that alcohol has. If you experience intense urges to drink alcohol, it is recommended to discuss these with a health professional.
What will happen if I take alcohol while taking fluoxetine?
- Increased sedation - Increases in sedation are the most pronounced interaction between alcohol and fluoxetine due to alcohol increasing inhibition in the brain [7].
- Exacerbation of symptoms - Alcohol is a depressant and can thereby exacerbate symptoms of depression, such as feelings of hopelessness, which interfere with carrying out daily tasks [7].
- Reduced effectiveness of fluoxetine - As alcohol can exacerbate symptoms of your underlying condition, alcohol can reduce the effectiveness of fluoxetine.
- Reduced effect of concurrent behavioral therapy - Fluoxetine and alcohol use may interact with ongoing therapy, reducing beneficial effects.
Some studies suggest that fluoxetine might decrease the desire to drink alcohol in some individuals [8]. However, other studies have found that fluoxetine treatment can result in poorer drinking-related outcomes in certain groups of alcoholics [9].
- Potential Health Risks - In less than 1% of individuals, drinking alcohol while taking fluoxetine can cause liver damage [10]. Although the risk is low, it is important to be aware of this effect.
What should I do if I drank alcohol while taking fluoxetine?
Drinking alcohol while taking fluoxetine, you should monitor your symptoms and avoid driving, operating heavy machinery or venturing into unknown areas. The compounded sedative effects of alcohol and fluoxetine increase the risks of accidents, falls or injuries [7].
It is essential to have the support of friends or relatives if you experience increased suicidal thoughts or low mood. You should seek medical attention if these thoughts occur more frequently.
Likewise, if you find yourself having strong urges to drink alcohol while taking fluoxetine, it's important to discuss these feelings with your healthcare provider. The healthcare professional can adjust your treatment plan if necessary and guide your treatment [7].
Interactions of Fluoxetine
Fluoxetine, a selective serotonin reuptake inhibitor (SSRI), interacts with several other substances. Although fluoxetine has fewer interactions than other classes of antidepressants, it is still vital to be aware of drug-drug interaction when taking fluoxetine.
- Monoamine Oxidase Inhibitors (MAOIs). MAOIs, for example selegiline, inhibit the enzyme called monoamine oxidase, which is critical to breaking down neurotransmitters. Taking MAOIs up to 5 weeks prior to fluoxetine can increase the effects of serotonin toxicity. This would result in fever, muscle spasms, muscle stiffness, heart rate and blood pressure changes, confusion and even loss of consciousness. Healthcare professionals will therefore always ask whether you have taken any MAOIs prior to prescribing fluoxetine [1, 11].
- Other antidepressants. Other antidepressants, such as escitalopram or serotonin-noradrenaline reuptake inhibitors, can interfere with the breakdown of fluoxetine. This would increase the levels of fluoxetine in the brain and thereby serotonin availability, increasing the risk of serotonin toxicity [12, ].
- Cytochrome P450 (CYP450) medication. CYP450 is a critical enzyme in the activation and breakdown of pharmacological substances. Drugs that are metabolized by this enzyme include aripiprazole, dextromethorphan, and risperidone. Fluoxetine can reduce the metabolism of these substances, increasing the risk of their side effects, combined with increased risk of fluoxetine-linked side effects []
- Non-steroidal antiinflammatory drugs (NSAIDs). Concurrent use of NSAIDs, such as aspirin, moderately increased the risk of gastro-intestinal side effects, such as gastric ulcers [15].
- Antipsychotic medication. Antipsychotic medication, such as olanzapine, has in the past been often co-prescribed with tricyclic antidepressants for the management of severe mental illnesses such as psychosis. More recently, SSRIs such as fluoxetine have replaced tricyclic antidepressants in this co-prescription due to lower side effects [16]. Thus combining fluoxetine with antipsychotics can be an effective strategy for managing severe psychiatric illnesses with reduced side effects.
To summarize, fluoxetine is among the most tolerable antidepressant SSRIs with low risks of side effects. Consuming alcohol can exacerbate symptoms of the underlying mental illness, but is unlikely to have severe physical adverse effects.
