December 5, 2021

Top 3 anesthesia side effects you need to know

Anesthesia side effects can be serious and Dr. Kaveh explains what you need to know about them, like pain, nausea, infection, nerve damage, and others.

Surgery can be a major trauma to your body. Anesthesia also affects your body, especially the brain. Together, these can cause side effects that can prolong your recovery and worsen pain. The good news: you can prevent most of the side effects of surgery and anesthesia. It takes preparation for surgery, just like you would prepare to give a speech.

Surgery can be a major trauma to your body. Anesthesia makes this safer and more comfortable. Side effects are common, but you can prevent nearly all of them.

Here are the top 3 anesthesia side effects my patients ask me about before surgery.

(1) Nausea side effect after surgery

This is one of the top anesthesia side effects my patients ask me about. And for a good reason: nausea can be common after surgery and anesthesia. It can affect 1 in every 3 patients. There are many causes of nausea after surgery, including:

  • The surgery itself. For example, abdominal and breast surgery are considered more likely to cause nausea.
  • Pain sensation. Feeling pain and discomfort after surgery can contribute to nausea.
  • Pain medication. Opioid pain medication after surgery can make you nauseous and constipated.
  • Anesthesia. Some anesthesia medications cause more nausea than others.
Nausea after surgery can be prevented if you tell your anesthesiologist before general anesthesia or sedation
Nausea after surgery is largely preventable if you let you anesthesiologist know

Unfortunately, many patients go on to fear nausea. Approaching your surgery with extra fear can add to your anxiety. Anxiety can worsen nausea!

The good news: the vast majority of nausea after surgery is preventable. It is important to tell your anesthesiologist about your concerns. Particularly, if you get sea sick, car sick, or motion sick, your anesthesiologist can help you. The more we know about your history, the better we can prevent your nausea after surgery.

The more I know about your history, the better I can prevent nausea side effects after your surgery.

(2) Constipation and opioid addiction after surgery

Nausea and constipation go hand in hand. 60% of patients after abdominal surgery can experience constipation after surgery. Pain and opioid pain medications are one of the main reasons patients get constipated after surgery.

When your body and brain experience pain, they "shut down" your bowels, causing you to get constipated. Opioid pain medication also "shuts down" your bowel. It's a double hit.

Additionally, the longer you use opioid pain medication, the higher the risk of opioid addiction. This can affect 1 in 4 patients after surgery. After just 5 days of pain meds, your risk significantly increases.

The good news: you can strongly control your pain experience after surgery. The better you understand your pain, the less opioid pain medication you need to use. By reducing pain, you can reduce your risk for constipation and opioid addiction after surgery. Meeting with your anesthesiologist before surgery can help you reduce these risks.

As a note, constipation after surgery is so common that it has many names. You may see it referred to as "post surgery constipation" or "postoperative ileus". See my upcoming article: "what foods to eat for constipation after surgery?"

(3) Sore throat side effect after surgery

Sore throat after surgery affects over 60% of patients. The sore throat is a side effect of anesthesia. It normally resolves within 2 days, but it can sometimes last longer than a week.

Sore throat after surgery can effect many patients, particularly after general anesthesia with a breathing tube
Sore throat after surgery is common but typically resolves quickly

But where does the sore throat after surgery come from?

The sore throat after surgery comes from a breathing tube. When you are under anesthesia, your breathing is decreased. In fact, many patients will stop breathing altogether under anesthesia. This is one reason why your anesthesiologist needs to place a breathing tube. The breathing tube connects you to a ventilator to help you breathe. It's like a "life support machine."

While the breathing tube is necessary to keep you alive during surgery, it can also cause sore throat because the plastic is sitting in your mouth.

Your anesthesiologist can help minimize your chance of sore throat after surgery. It depends on:

  • Your pre-existing medical conditions.
  • The type of surgery.
  • Foods you eat before surgery.
  • Herbs you take after surgery.

Speaking with your anesthesiologist before surgery can help reduce sore throat and make you more comfortable as you recover.

Other anesthesia side effects my patients ask me about

There are many other anesthesia side effects my patients ask me about. Some of these side effects after surgery are:

  • Memory loss and dementia after surgery and anesthesia.
  • Pain after surgery.
  • Weight gain after surgery.
  • Depression after surgery,

Always ask your anesthesiologists your questions - don't be shy! You can reduce your risk for many side effects by preparing for your surgery.


Apfel et al. "PONV: a problem of inhalational anaesthesia?." Best Practice & Research Clinical Anaesthesiology 19.3 (2005): 485-500.

Burkle et al. Patient fear of anesthesia complications according to surgical type: potential impact on informed consent for anesthesia. Acta Anaesthesiol Scand. 2014 Nov;58(10):1249-57.

Ruhaiyem et al. Fear of going under general anesthesia: A cross-sectional study. Saudi J Anaesth. 2016;10(3):317-321.

Van den Bosch, et al. Does measurement of preoperative anxiety have added value for predicting postoperative nausea and vomiting? Anesth Analg. 2005 May;100(5):1525-32, table of contents. doi: 10.1213/01.ANE.0000149325.20542.D4. PMID: 15845719.

Barbieux, J., et al. "Does enhanced recovery reduce postoperative ileus after colorectal surgery?." Journal of visceral surgery 154.2 (2017): 79-85.

Tick, Heather, et al. "Evidence-based nonpharmacologic strategies for comprehensive pain care: the Consortium Pain Task Force white paper." Explore 14.3 (2018): 177-211.

El‐Boghdadly, K., C. R. Bailey, and M. D. Wiles. "Postoperative sore throat: a systematic review." Anaesthesia 71.6 (2016): 706-717.

Correll et al, Value of Preoperative Clinic Visits in Identifying Issues with Potential Impact on Operating Room Efficiency. Anesthesiology 2006; 105:1254–1259

Higgins, P. P., F. Chung, and G. Mezei. "Postoperative sore throat after ambulatory surgery." British journal of anaesthesia 88.4 (2002): 582-584.

Biro, Peter, Burkhardt Seifert, and T. Pasch. "Complaints of sore throat after tracheal intubation: a prospective evaluation." European Journal of Anaesthesiology (EJA) 22.4 (2005): 307-311.

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