Introduction
Fluoxetine is one of the most commonly prescribed antidepressants and is widely tested in the OPRA (Overseas Pharmacist Readiness Assessment) exam. To work in an advanced healthcare sector like that in Australia, a pharmacist who knows the adverse effects, monitoring parameters, and patient counselling points is essential for safe clinical practice. This guide covers everything you need to know about the adverse effects of fluoxetine, along with key concepts, FAQs, and study tips to help you ace your OPRA exam
What is Fluoxetine?
Fluoxetine is a selective serotonin reuptake inhibitor (SSRI) antidepressant. It works by increasing the levels of serotonin, a chemical messenger in the brain. This improves mood and physical symptoms of depression and also relieves symptoms of panic and obsessive disorders.
Key Adverse Effects of Fluoxetine
| System | Common Adverse Effects | Adverse effects |
| Central nervous system | Insomnia, headache, anxiety, nervousness, tremor | Seizures, mania/hypomania activation, serotonin syndrome |
| Gastro intestinal | Nausea, diarrhea, dry mouth, anorexia | bleeding |
| sexual | Decreased libido, delayed ejaculation, anorgasmia | Persistent sexual dysfunction |
| Metabolic/Weight | Weight loss (initial), appetite suppression | Long-term weight gain possible |
| Dermatological | Sweating, rash | Stevens-Johnson syndrome (rare) |
| Cardiac | Palpitations | QT prolongation (rare, high dose/interaction) |
| Others | Fatigue, yawning | Hyponatremia (SIADH), especially in elderly |
Expert Advice for Fluoxetine usage
- Take Fluoxetine in the morning since it can keep you awake if taken late at night.
- It may cause anxiety and agitation when you first start taking it.
- It may cause weight loss and decreased appetite.
- Don’t drive or do anything requiring concentration until you know how Fluoxetine affects you.
- Talk to your doctor if you notice sudden mood changes or develop suicidal thoughts.
- Inform your doctor if you experience difficulty having an orgasm or have decreased sex drive.
- The addiction/dependence potential of Fluoxetine is very less.
- Do not stop treatment suddenly without consulting your doctor as that may lead to agitation, anxiety, and dysphoria.
- It can take 2-3 weeks for Fluoxetine to start working.
- Do not stop treatment suddenly as this may cause an upset stomach, flu-like withdrawal symptoms and sleep disturbance.
- If your doctor asks you to stop Fluoxetine, you should reduce the dose slowly over 4 weeks.
- Avoid consuming alcohol when taking Fluoxetine, as it may cause excessive drowsiness and calmness.
- The addiction/dependence potential of Fluoxetine is very less.
Key features
- The most common anti-depressant prescribed globally is SSRI. Fluoxetine is one of the common prescribed SSRI
- Half life of fluoxetine is approximately 4-6 hours
- Common side effects of Fluoxetine are related to CNS, GI, and sexual dysfunction.
- There is a risk of serotonin syndrome when combined with MAOIs, triptans, or linezolid.
- Preferred for patients with fatigue due to its activating effect.
Conclusion
One popular SSRI with a well-known safety record is fluoxetine. Fluoxetine is always having serious side effects such as serotonin syndrome, seizures, or QT prolongation that require monitoring.
However, the majority of side effects are minor and temporary. Patients should pay attention to the drug interactions, side effects, mechanism of action, and counseling points when preparing for competitive exams like the OPRA exam.
