The length of time that the side effects of Celexa last vary between each individual. Most of the side effects go away once the patient's body adjusts to the medication, according to Drugs.com. It takes approximately one to four weeks for patients to begin to feel the full effects of Celexa.
The most common side effects of Celexa include increased tiredness and decreased sexual desire. Other known side effects include headaches, heartburn, skin tingling, increase or decrease in weight, muscle pain and increased sweating. If the side effects of Celexa do not go away after some time, a doctor may decide to gradually lower the dose of the medication. Patients should never stop taking the medication without consent from a medical professional.