What are the Effects of Prozac as an Antidepressant?

Prozac as an Antidepressant Video

Prozac (fluoxetine) is an antidepressant in the selective serotonin reuptake inhibitor (SSRI) class of drugs.

It is given to treat major depressive disorder, panic attacks, obsessive-compulsive disorder, bulimia, & premenstrual dysphoric disorder (a severe form of premenstrual syndrome). It also has some off-label uses including fibromyalgia, migraines, & raynaud phenomenon.

Prozac is usually started at 20 mg/day orally in the morning. The dose may be increased after several weeks if improvement is not observed, but not to exceed 80 mg/day.

Prozac (fluoxetine) is given to treat:

   Major depressive disorder
Panic attacks
Obsessive-compulsive disorder
Premenstrual dysphoric disorder
(a severe form of premenstrual syndrome)

Off-label uses:

Raynaud phenomenon

Dosage: 20 mg/day up to 80 mg/day

Adverse effects of Prozac include:

    GI symptoms - nausea, diarrhea, loss of appetite,
weight loss
Sexual dysfunction
CNS stimulation - anxiety, nervousness, insomnia
Increased risk of GI bleeding - worsened by the use of
NSAIDS, aspirin, or warfarin

There is a Black Box Warning for Prozac & all antidepressants – When given for depression, Prozac has been shown to cause an increase in the incidence of suicidal thoughts in patients under age 24. Therefore, children & young adults should be closely observed if drug therapy is started.

When considering Prozac use during pregnancy, several things should be kept in mind:
Prozac falls in pregnancy category C (animal studies show adverse effects on the fetus and there are no adequate, well-controlled studies in humans, but benefits may account for use of the drug despite the risks).

Some studies have shown heart malformations in newborns and prolonged hospitalization with respiratory support needed.

Prozac is in the lactation category of L3 for neonates &
L2 for older infants, which means it is probably compatible
but there are no controlled studies & unforeseen effects to
the breastfed infant are possible. The benefits of the drug
have to be weighed against the risks.

Drug interactions
If the patient will be switching from an MAOI (monoamine oxidase inhibitor) to Prozac (or any SSRI), there should be at least a 14 day lapse between the drugs. When switching from Prozac to an MAOI, Prozac should be discontinued at least 5 weeks before starting the MAO inhibitor.

Serotonin syndrome is a serious and sometimes fatal reaction that may occur when an SSRI and an MAO inhibitor are combined. It is characterized by the following symptoms:

    Mental status changes - agitation, delirium, coma
Autonomic instability - tachycardia, labile BP, dizziness,
Neuromuscular symptoms - tremor, muscle rigidity,
incoordination, seizures
GI symptoms - nausea, vomiting, diarrhea

The risk of serotonin syndrome increases if other drugs are taken that also increase serotonin; including other antidepressants, street drugs such as ‘ecstasy,’ St. John’s wort, and tryptophan, among others.

Education for the patient taking Prozac:

– Tell the doctor right away if you notice worsening depression or other psychiatric conditions, unusual changes in behavior or mood, or suicidal thoughts.
– Some improvement should be seen within 1-2 weeks, but it may take 4-5 weeks before feeling the full benefit of the medication.
– If diabetic, Prozac may affect blood sugar levels, therefore regularly monitor your blood sugar & the doctor may need to make adjustments to medication or diet.
– The drug may cause dizziness or drowsiness, so avoid driving or using machinery until you are sure such activities can be performed safely.
– Avoid alcoholic beverages.
– Inform the doctor or pharmacist if you are taking other products that cause drowsiness including antihistamines, drugs for sleep or anxiety, muscle relaxants, narcotic pain relievers, or alcohol.
– Do not stop taking Prozac without first consulting your healthcare provider – some conditions may become worse or even severe when the drug is stopped abruptly. It is best if the dose is gradually decreased under the doctor’s supervision. The effects of the drug decrease slowly, over 2-3 months.
– Prozac can stay in the body for many weeks after the last dose & may still interact with other medications. It is important to tell your healthcare provider if Prozac has been taken in the previous 5 weeks before taking any other medication.
– Medication should be stored away from light & moisture – do not store in the bathroom.
– Do not flush medications down the toilet or pour them in a drain.
– Keep all medications away from children & pet


Return to Patient Care Videos



by Mometrix Test Preparation | This Page Last Updated: July 20, 2023