Ketamine Side Effects

by on March 15, 2012


Ketamine is an anesthetic drug that has a number of benefits, but it can also cause a variety of side effects.  These can range from common effects like mood changes, drowsiness, or vomiting to more serious issues like delirium, hallucinations, or amnesia. These ketamine side effects can worsen in special populations like the elderly or pregnant women. Additionally, side effects can also occur when ketamine is taken in combination with other medications or alcohol. Additional information about the uses of ketamine and the potential ketamine side effects is discussed at length below.

Common Ketamine Side Effects

Most medications have the ability to cause side effects, but these are minor in most cases. The following side effects are common and are not a cause for concern unless they worsen, become increasingly bothersome, or do not go away:

  • Drowsiness
  • Mood changes
  • Vomiting
  • Difficult sleeping
  • Changes in appetite
  • Jerky muscle movements
  • Nightmares
  • Nausea
  • Confusion
  • Changes in heart rate or blood pressure

It is also common for patients to feel slightly confused or strange when they are first waking up after anesthesia.

Serious Ketamine Side Effects

ketamine Some of the most frequently experienced serious side effects of ketamine are due to an allergic reaction. If this occurs, it is important to seek medical attention immediately. Some of the most common serious side effects include:

  • Rash
  • Swelling of the skin
  • Hives
  • Swelling of the tongue, lips, face, and mouth
  • Tightness in the chest
  • Difficulty breathing

Other serious side effects may occur, but these are rare. However, if patients do experience them, they should be sure to seek medical treatment right away. These serious side effects include:

  • Flashbacks
  • Loss of coordination
  • Delirium
  • Amnesia
  • Unusual thoughts
  • Extreme and unreasonable fear
  • Muscle rigidity
  • Tachycardia
  • Loss of touch with reality
  • Aggressive or violent behavior

Ketamine Withdrawal and Dependence

Several studies of ketamine have shown that users can develop a dependence or tolerance to the medication. Tolerance can develop to the point where patients will no longer experience the dissociative effects that they felt when they first started using the medication. Ketamine dependence may also occur in similar forms to dependence on other drugs like alcohol, opiates, and stimulants. Some users will repeatedly binge on the drug in excessive amounts within a short period of time, and research is still ongoing regarding ketamine side effects of withdrawal.

Ketamine and Breast Feeding

Ketamine has not been formally assigned by the FDA to a pregnancy category. Animal studies have failed to reveal any impairment of fertility, but there have not been any controlled data in human pregnancies. Safe use in pregnancy has not been determined, but manufacturers recommend that ketamine be used cautiously in pregnancy. Breastfeeding is also not recommended, as ketamine is a general anesthetic agent. Nursing is not recommended until 12 hours after a dose has been taken.


Alcohol may worsen some of the pharmacological effects of CNS-active agents, and using ketamine in combination with alcohol can create additional depression of the nervous system as well as impairment of psychomotor skills, thinking, and judgment. Patients receiving ketamine may be warned about these interactions and will be told to limit or avoid consumption of alcohol. Hazardous activities that require motor coordination or mental alertness should be avoided until patients understand how the medication will affect them.

Ketamine is a powerful anesthetic that is intended for usage during surgical procedures in order to prevent pain and discomfort. However, ketamine side effects can also occur. These can range from common effects like mood changes, drowsiness, or vomiting to more serious issues like delirium, hallucinations, or amnesia. Side effects are more to occur when this medication is taken appropriately, in combination with other medications, or with alcohol. Pregnant women are also discouraged from taking ketamine, and nursing mothers should also avoid it. By understanding these potential ketamine side effects, patients can determine whether the benefits of this medication outweigh any potential risks.