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Prozac (Fluoxetine) Information

Prozac (fluoxetine hydrochloride) is a prescription medication and one of the earliest drugs belonging to the class of Selective Serotonin Reuptake Inhibitors (SSRIs). It is indicated for a broad range of psychiatric conditions, including Major Depressive Disorder (MDD), Obsessive-Compulsive Disorder (OCD), Panic Disorder (PD), and Bulimia Nervosa (BN). Its versatile application and relatively activating properties make it a foundational treatment for many mental health issues. Fluoxetine is unique among the SSRIs for its very long half-life of 4 to 6 days for the parent compound, and 9 to 10 days for its major active metabolite, norfluoxetine. This long half-life minimizes the risk of severe withdrawal symptoms upon discontinuation and allows for weekly-dosing formulations. Consistent daily (or weekly) use is essential for this medication, as the therapeutic effect often takes several weeks to develop fully.

The mechanism of action for fluoxetine is its potent and highly selective inhibition of the Serotonin Transporter (SERT). By blocking the reuptake of the neurotransmitter serotonin (5-HT), fluoxetine increases the concentration and duration of serotonin activity in the synaptic clefts. This enhanced serotonergic activity is believed to correct the chemical imbalances that contribute to the symptoms of depression, anxiety, and compulsive behaviours. This prolonged presence in the body means that any dose change or switch to another drug requires careful management and an extended waiting period. Prozac is available in Canada as a prescription-only medication in capsule, tablet, and oral solution forms. Dosing is highly individualized, starting low (e.g., 20 mg/day) and gradually increasing the dose. For MDD, the typical dose is 20-40 mg daily. In comparison, the treatment of Bulimia Nervosa requires a higher dose of 60 mg daily. Unlike many other antidepressants, fluoxetine is approved for use in children and adolescents (8 years of age and older) for the treatment of MDD and OCD when prescribed under specialist supervision.

Prozac Side Effects

While Prozac is generally well-tolerated, some individuals may still experience side effects, many of which are related to its activating properties. The most common effects reported include insomnia, headache, anxiety, nervousness, tremor, and gastrointestinal issues such as nausea or diarrhea. Loss of appetite and weight loss are also common, particularly at the beginning of treatment. Sexual dysfunction (e.g., decreased libido, ejaculatory or orgasmic delay) is a common side effect associated with all SSRIs.

However, more serious side effects can occur, although they are rare. If any of the following symptoms are experienced, the patient should stop taking the medication and seek immediate medical attention:
• Mania/Hypomania: The drug's activating properties can potentially trigger a manic or hypomanic episode, particularly in patients with undiagnosed bipolar disorder, requiring immediate medical evaluation.

• Severe Allergic/Cutaneous Reactions: Although rare, fluoxetine can cause severe systemic reactions, including vasculitis and serum sickness, as well as a severe skin rash that may progress to a serious, life-threatening illness. The drug must be discontinued immediately if a rash develops.

• Serotonin Syndrome: This is a potentially life-threatening reaction that results from an excessive amount of serotonin, typically when Prozac is combined with other serotonergic drugs (e.g., MAOIs, triptans, tramadol). Symptoms may include agitation, hallucinations, a rapid heart rate, fever, muscle rigidity, and incoordination. Due to the drug's long half-life, a long washout period is required when switching.

• Suicidality and Worsening of Depression (Boxed Warning): Antidepressants, including Prozac, carry a strong risk warning for increasing the risk of suicidal thoughts and behaviour, particularly in young adults (under 25) and children/adolescents, especially during the initial phase of treatment or following a dose change.

Prozac Precautions

Before taking Prozac, it is essential to have a thorough discussion with a healthcare provider about your medical history and any other medications you are taking. Prozac is absolutely contraindicated for use with Monoamine Oxidase Inhibitors (MAOIs) due to the severe risk of Serotonin Syndrome. Due to its long half-life, a minimum five-week washout period is required after stopping fluoxetine before starting an MAOI. It is also contraindicated with the antipsychotics thioridazine and pimozide due to the combined risk of severe cardiac arrhythmias. Caution is required in patients with a history of seizure disorder or mania/hypomania. Since fluoxetine can cause weight loss and appetite suppression, it should be used with caution in patients who are already underweight or have a history of significant weight loss. Like other SSRIs, fluoxetine can impair platelet aggregation. It should be used with caution in patients with a history of bleeding disorders or those concurrently taking anticoagulants (e.g., warfarin) or NSAIDs. Due to its long half-life, dosage adjustments or switches to other drugs require extra caution and monitoring. If you are pregnant or breastfeeding, the risks and benefits must be carefully weighed with your doctor.

Do I need a prescription to order Prozac?

Yes, a prescription is required from your physician to order Prozac.