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Side Effects of Anesthesia - Know It All

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Anesthesia is used in many surgeries to numb the body areas required for surgery. This topic presents anesthesia, its uses, and its side effects.

Medically reviewed by

Dr. Kaushal Bhavsar

Published At August 29, 2023
Reviewed AtNovember 10, 2023


Anesthesia is medicine delivered by doctors before initiating any surgery. Anesthesia is used as a medicine to block the pain sensations going to the brain. Anesthesia is of different types and is even delivered in different modes. Anesthesia delivered through inhaling the agents are inhalational agents and anesthesia delivered through injecting intravenously are called the intravenous method. This topic elaborates on anesthesia, its use, and the side effects it causes.

What Is Anesthesia?

Anesthesia is the medicine that relieves the feeling of pain during procedures or surgery. Different types of anesthesia block the pain differently. Some anesthetics or medications numb particular body regions, while others render patients unconscious and numb their brains. Local anesthesia, regional anesthesia, and general anesthesia are the anesthesia, a doctor uses to numb the patient.

How Does Anesthesia Work?

Anesthesia medicine blocks the pain sensation going to the brain by blocking the nerve supply associated with the targeted body area. The nerve supply that sends the messages of feeling or pain sensations is inhibited by anesthesia.

What Are the Different Types of Anesthesia?

Different types of anesthesia are:

  • Local Anesthesia - Local anesthetics are used to numb the small body area. Sprays, gels, or injections can deliver it. It blocks the small area of nerve supply only.

  • Regional anesthesia - It is used to numb the large body part by blocking a more significant or major nerve supply from the spinal areas. Injections deliver regional anesthesia over the targeted site or nerve. It is used in surgeries like knee replacements and cesarean sections for delivery.

  • General Anesthesia - In general anesthesia, the patient goes unconscious after getting anesthesia. It is used in many heavy surgeries like heart or brain surgery. The body's nervous system relaxes, and the patient sleeps deeply.

Who Administers the Anesthesia?

Anesthesia, if delivered by injection or inhaled by gases, requires the serious attention of a doctor who is specialized in anesthesia (anesthesiologist) to administer anesthesia. But local anesthesia can be administered by other doctors, like dentists or surgeons, to proceed with their procedures painlessly.

What Are the Uses of Anesthesia?

Anesthesia is used in many fields to numb body parts. A few uses of anesthesia are :

  • In the surgeries to block the nerve sensations.

  • After the surgery as, analgesic medication, to control the pain post-surgery.

  • In dental procedures.

  • In skin procedures.

  • Other minor procedures like biopsy or draining pus.

  • In the nerve blocking to prevent unbearable pain by the patient.

What Happens After Anesthesia?

The patient starts feeling heaviness over the area, where anesthesia is delivered. Next, the patient starts having a tingling sensation over an area, and soon numbness occurs with loss of sense.

What Are the Precautions Taken After Anesthesia?

The precautions taken after anesthesia are:

  • The patient should not drive back home.

  • The patient should take complete rest for at least one entire day.

  • The patient should avoid alcohol for at least 24 hours.

  • The patient should take the medication after the doctor's consultation.

What Are the Side Effects of Anesthesia?

Side effects of anesthesia include:

  • Shivering.

  • Chills.

  • Fever.

  • Headache.

  • Low body temperature.

  • Itchiness.

  • Nausea and vomiting.

  • Sore throat.

  • Pain and soreness over the site of injection.

  • Low heart rate.

  • Fatigue.

  • Difficulty in urinating.

What Are the Adverse Side Effects of Anesthesia?

Using anesthesia does cause some severe effects. Adverse side effects of anesthesia are:

  • Lung Collapse - The use of general anesthesia can cause unconsciousness and breathing difficulty. The doctor maintains the breathing of the patient. In very rare cases, lung collapse can still occur.

  • Anesthesia Awareness - Sometimes, the patient gets less anesthesia dose, which may be delivered intentionally or unintentionally by the doctor. The patient becomes conscious of the surroundings instead of being completely unconscious. But the patient possibly does not feel the pain.

  • Nerve Damage - Nerve damage can occur in the patient. The nerve damage can be temporary or permanent. Accordingly, numbness, pain, or weakness can appear.

  • Postoperative Delirium - The old age patient is more prone to postoperative delirium. Delirium causes the patient to have confusion, altered consciousness, and disorganized thinking. Sometimes, the patient can experience long-term memory loss too.

Who Are at Risk of Developing Adverse Side Effects?

Some patients are at risk of developing adverse side effects after anesthesia. They are:

  • Older patients.

  • Diabetic patients.

  • Patient with a family history of malignant hyperthermia.

  • Patient with high blood pressure.

  • Obese patients.

  • Sleep apnea.

  • Alcoholic or smoker patient.

  • Patient with seizures.

How Long Does Anesthesia Last?

Anesthesia can stay for as long as 24 hours, depending on the quantity of dosage the doctor has delivered. Usually, anesthesia remains in the body for about four to five hours. Therefore, the patient should avoid regular body function from the targeted anesthetic site until the anesthesia has its effects.

How Does Anesthesia Affect Pregnancy and Breastfeeding Mothers?

The anesthesia is entirely safe in pregnancy, as many pregnant women go for regional anesthesia during C-sections.

In breastfeeding mothers, anesthesia is ideally safe, but it depends upon the anesthetic agents used by the doctor. Sometimes, the doctor recommends the breastfeeding mother lapse for 24 hours after anesthesia. The anesthetic agents leave the system entirely within 24 hours and will not excrete in the mother's milk.

Can Children Have the Benefit of Anesthesia?

Yes, anesthesia can be used in child patients as many procedures require pain-controlling anesthesia that makes the child cooperate with the doctor on receiving no pain sensation over the surgery site.

Is Anesthesia Safe to Have?

Yes, anesthesia is an entirely safe procedure. And it is popular and beneficial for both the patient and the doctor. The patient feels no pain, and the doctor delivers the anesthesia after the infiltration process.


Anesthesia is a pain-controlling medication the doctor delivers to the patient during any surgical procedure. It is a practical step before starting the surgery; the use, side effects, and adverse side effects are mentioned. Some of the side effects of anesthesia can be itchiness, fever, headache, nausea, vomiting, chills, and shivering. Some adverse effects include lung collapse, postoperative delirium, and nerve damage.

Dr. Kaushal Bhavsar
Dr. Kaushal Bhavsar

Pulmonology (Asthma Doctors)


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