What Is a Drug-induced Coma?
A coma is defined as a state of unconsciousness other than sleep.1
And while it can happen naturally as a response to trauma or overdose, the term “drug-induced coma” (or “medically-induced coma”) refers to the medical practice of purposefully putting a patient into a prolonged state of unconsciousness using a controlled dose of sedative medications.
Due to the risks involved, medically induced comas are rarely used – and even then, they are usually reserved for cases of the worst brain trauma, seizures or infection.
Drug-induced Coma Quick Facts
- Drug-induced comas are a medical state induced by a doctor.
- A low, controlled dose of a barbiturate or other sedative drug is administered in order to maintain the patient’s coma state.
- There are a number of different medical purposes and benefits that may be gained by inducing a coma.
- There are possible complications that can occur – and these complications must be weighed against the potential benefits.
Why Are Drug-induced Comas Used?
Drug-induced comas are used to protect the brain.They work by minimizing the energy expenditure of brain cells and by minimizing or preventing brain swelling.
Therapeutic, medically-induced comas are generally resorted to only after conventional treatment measures fail to keep brain swelling down.
Reasons to Induce a Coma
There are a number of different medical reasons to induce coma in a patient.
- To control brain swelling.
- To mitigate harm during a prolonged seizure.
- To provide the patient with time to heal.
- To allow the brain to rest.
What Happens to the Brain During a Drug-induced Coma?
During a medically-induced coma, the brain is temporarily set into a coma state with the use of certain sedative medications.
The Brain in a Coma
During a coma, the brain continues to function but at its lowest level of alertness. Basic functions like breathing and heart rate remain constant, and the patient may have a reflex response to touch or pain. Signs of understanding what is said or done around him may also be reflexive but it is often suggested that family members talk to their loved one in a coma as if they were aware and conscious.2
What Sedative Medications Are Used?
The sedatives used for drug-induced comas are selected to cause totally reversible comas without also causing any brain damage. Some medications used in drug-induced comas to reduce brain swelling may include:
- Propofol. Propofol is a general anesthetic that is sometimes preferred for its short-acting properties. It’s sedative effects are near-immediate, but they only last for minutes after intravenous infusion has stopped. That means that healthcare personnel may intermittently conduct clinical neurological assessments as they monitor the patient during the coma. Studies have even suggested that propofol may have protective effects on the brain and lead to better and quicker patient recovery compared to those of patients on morphine sedation.3-6
- Barbiturates. Barbiturates such as pentobarbital or thiopental have been the traditional drugs of choice for drug-induced comas. While these drugs appear to reduce brain swelling like propofol does, one study on pentobarbital was not able to demonstrate improved patient mortality after 30 days.
- Benzodiazepines. Midazolam (trade name, Versed) is one example of a benzodiazepine that has been used for drug-induced comas lasting longer than 72 hours.
- Opiates. Opiates such as morphine and fentanyl have also been used to induce comas.
Drug-induced Coma vs. Sedation
The American Society of Anesthesiologists argues that a medically-induced coma differs from sedation because it is only administered in intensive care units and causes the patient to enter a deeply unconscious state – while sedation is said to occur in hospitals, doctors’ offices and ambulatory surgery units and only cause the patient to enter a semi-conscious state.7
Others, such as Dr. Stephen Mernoff – the neurology co-chief Roger Williams Medical Center – don’t make such a distinction between the two. Those who side with Dr. Mernoff’s perspective state that a coma is any unconscious state other than sleep.1
How the Brain Benefits From a Drug-induced Coma
The brain is the most active organ in the body. It is due to the brain’s activity that we dream, wake up in the morning, continue to breathe and experience regular heart beats – no matter what our focus or activity.
The pipeline of blood into the brain is highly active as the brain continually draws from it the nutrients, oxygen and glucose it needs to function. If this pipeline become blocked by a blood clot, a stroke can develop. If it becomes dysfunctional and allows too much blood to enter, the brain must work harder and often swells as a result. But since a hard, immovable skull encases the brain, there is no room for the swelling to occur as it attempts to heal itself.
When a doctor uses drugs to induce a coma, brain activity is limited – giving it a chance to rest and heal without swelling further and potentially causing more damage.
How Long Does the Drug-induced Coma Last?
The length of your drug-induced coma may vary, depending on the reasons you’ve been put in a temporary coma and depending on how quickly the treatment helps reduce swelling in the brain.
Some may only need to be in a medically-induced coma for as little as 12 hours – while others may be under for weeks. It’s important to talk with your healthcare provider who can give you more specific information on the length of your drug-induced coma.
Potential Complications of Drug-induced Coma
Though there can be great reward to inducing a coma in a patient, it is only a last ditch effort used when nothing else is achieving the desired medical results. This is because there are a number of complications that can develop from a drug-induced comas1,8:
- Lowered blood pressure.
- Weakened heart muscle.
- Heart failure.
- Impaired circulation.
- Vulnerability to infections.
- Coming out of the coma in a vegetative state.
Safety Measures During a Drug-induced Coma
Since drug-induced comas do come with certain risks, safety measures are typically taken to help monitor and minimize these risks1,3,8:
- Patient brain waves can be monitored by electroencephalography (EEG).
- Intracranial pressure can be measured by inserting into the patient’s head a fiberoptic tube that monitors blood flow.
- The Glasgow scale is also often used to clinically monitor a patient neurologically. This neurological test is a clinical numerical measure of the patients’ ability to respond to verbal and other stimuli.
- Some doctors prefer using the medication propofol because it is short-acting and allows for more intermittent neurological monitoring.
Alternatives to Medically Inducing a Coma
If you nervous about the possible risks that an induced coma may hold for a loved one in the hospital, you are encouraged to ask your healthcare provider about alternative treatments. Alternative treatments are more and more often taking the place of drug-induced comas and may include1:
- Hypothermia: lowering the patient’s body temperature.
- Craniectomy: removing part of the skull so that the brain may have more room to swell without damage.
Learn More and Get the Help You Need
The concept of a ‘drug-induced coma’ can mean different things depending on the situation with which it applies. In the case of this article, we discuss therapeutic, medically-induced comas which may be beneficial in some hospital settings. Others might be seeking information on a coma to have resulted from a drug overdose, and resultant anoxic brain injury. Still others might be interested in finding out more info about the general anesthetic procedures utilized throughout ultra-rapid detox programs for substance abuse recovery. If you have a question about substance abuse treatment options for yourself or a loved one in need, call us at 1-888-744-0789.
- Connolly, C. (2006). Slowing down the brain is still fraught with risk. The Washington Post.
- Head injury: a family guide. South Carolina Department of Disabilities and Special Needs.
- Skoglund, K., Enblad, P., Marklund, N. (2009). Effects of the neurological wake-up test on intracranial pressure and cerebral perfusion pressure in brain-injured patients. Neurocrit Care, 11(2), 135.
- Rossaint, J., Rossaint, R., Weis, J., Fries, M., Rex, S., Coburn, M. (2009). Propofol: neuroprotection in an in vitro model of traumatic brain injury. Crit Care, 13(2), R61.
- Kelly, D. F., Goodale, D. B., Williams, J., Herr, D. L., Chappell, E. T., Rosner, M. J., et al. (1999). Propofol in the treatment of moderate and severe head injury: a randomized, prospective double-blinded pilot trial. J. Neurosurg., 90(6), 1042.
- McKeage, K., Perry, C. M. (2003). Propofol: a review of its use in intensive care sedation of adults. CNS Drugs, 17(4), 235-72.
- Medically induced coma vs. sedation. Lifeline to Modern Medicine, American Society of Anesthesiologists.
- Medical comas: how and when they’re used. (2006). NPR podcast.
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