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Side Effect: Decreased Appetite/Weight Loss

What is Decreased Appetite/Weight Loss?

Weight loss, also referred to as cachexia in severe cases, can affect a large portion of cancer patients. Weight loss is commonly accompanied by decrease appetite, but cancer patients who are eating adequate amount of food still can experience weight loss due to increases in inflammation and body metabolism. Decreases in weight and body mass can lead to decreases in quality of life, response to chemotherapy, and overall survival of cancer patients.

What does Decreased Appetite/Weight Loss look like?

Patients are considered to have clinically significant weight loss if they experience unintended weight loss of 5% of their weight or more in less than 6 months or 2% or more in patients who already had low body weight. In most cases, this results in visual decrease in fat and muscle mass and very low energy levels.

Decreased Appetite/Weight Loss

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Who gets Decreased Appetite/Weight Loss?

Patients who experience weight loss can vary depending on the type of cancer they have. For instance, it has been reported that as high as 80% of patients with cancer that involves the stomach or pancreas experience weight loss while approximately 40% of patients with breast cancer are affected. For all cancer patients, the number of patients that experience weight loss is much higher as they near death.

How to treat Decreased Appetite/Weight Loss

In some cases, weight loss can be improved after starting therapy to treat the underlying cancer if the disease is the main reason for the weight loss. In other cases, the most common approach to addressing weight loss is to increase appetite and therefore increase the total amount of calories that are eaten per day to make up for the increase in calories that are being used up by the body.

Megestrol (Megace®)
Megestrol is thought to increase appetite by releasing hormones that promote appetite and by decreasing inflammation as well. It is an oral tablet or suspension that can be taken once or twice a day. It can increase risk of blood clots so megestrol may not be a good option if you are at high risk for or have a history of blood clots

Corticosteroids (Prednisone, Methylprednisolone, Dexamethasone)
Corticosteroids can be given to help stimulate appetite by decreasing inflammation and increasing signals the body uses to increase appetite. Although they can be effective, the benefits are usually only seen for a few weeks and there are many possible side effects from taking these medications. In the short term, they can cause increases in blood sugar, blood pressure, and cause mood swings or trouble sleeping. In the long term, these medications can cause muscle loss, swelling, skin thinning, weak bones, and increase risk of infections.

Cannabinoids (Dronabinol (Marinol®)
Prescription cannabinoids contain the active ingredient in marijuana, tetrahydrocannabinol (THC), which stimulates appetite. While these medications can increase appetite and improve mood, they can also cause drowsiness, dry mouth, difficulty thinking and, in some cases, can cause extreme paranoia or hallucinations.

Mirtazapine (Remeron®)
Mirtazapine is an anti-depressant but can help stimulate appetite by blocking a receptor in the brain which results in increased food intake. This medication is generally well tolerated but can cause drowsiness, dry mouth, and blurry vision. When stopping this medication, is important to slowly lower the dose over time (taper) and not stop suddenly as this can cause withdrawal symptoms.

This medication blocks the action of serotonin, which can suppress appetite. It may only have a mild effect of stimulating appetite and can cause excessive drowsiness.


1) Sadeghi M, Keshavarz-Fathi M, Baracos V, et al. Cancer cachexia: Diagnosis, assessment, and treatment. Crit Rev Oncol Hematol 2018;127:91-104
2) Hariyanto TI and Kurniawan A. Appetite problem in cancer patients: Pathophysiology, diagnosis, and treatment. Cancer Treat Res Commun 2021;27:100336
3) Nishikawa H, Goto M, Fukunishi S, et al. Cancer Cachexia: Its Mechanism and Clinical Significance. Int J Mol Sci 2021;22:8491
4) Aoyagi T, Terracina KP, Raza A, et al. Cancer cachexia, mechanism and treatment. World J Gastrointest Oncol 2015;7:17-29

Created: November 8, 2023 Updated: November 8, 2023