What is Clonidine Toxicity?
Clonidine is a regularly prescribed medication with various medical uses. While it was initially developed as a drug to clear up congested noses, it is most commonly used to treat high blood pressure. Nowadays, it’s also being used more frequently to treat behavior and sleep disorders in children, such as ADHD, Tourette syndrome, and sleep disturbances. The drug has shown promise in treating different types of substance withdrawal as well. Clonidine works by interacting with certain receptors in the body, specifically alpha-2, imidazoline, and mu receptors. If someone takes too much Clonidine, it can lead to symptoms that are not easily recognizable.
Even when taken properly, Clonidine can cause side effects like dry mouth, constipation, and sleepiness. However, if someone accidentally takes an overdose, it can affect their heart and blood pressure stability and even cause depression.
What Causes Clonidine Toxicity?
Clonidine toxicity, or poisoning, can happen for a few reasons. It might be because too many skin patches are used at once or if someone accidentally or intentionally takes too many of the tablet forms of the medication.
Risk Factors and Frequency for Clonidine Toxicity
Over the recent years, doctors have started prescribing clonidine more often as they’ve found more health situations where it can be used. However, this has led to more people misusing the drug or accidentally taking it. A study that looked at data from the National Poison Data System found that the number of kids accidentally exposed to drugs like clonidine, known as alpha-2 agonists, has increased by about 5.9% each year from 2000 to 2011. Out of all the alpha-2 agonists, clonidine was the most commonly reported in these cases. It also had the highest number of moderate to severe outcomes when compared to two other similar drugs, guanfacine and tizanidine.
Signs and Symptoms of Clonidine Toxicity
Clonidine poisoning typically leads to symptoms like drowsiness, difficulty in breathing, low blood pressure, slow heartbeat, and small pupils. Usually, people show changes in consciousness level within 90 minutes, even before any heart-related symptoms, which tend to show up within 4 hours. Interestingly, some individuals who consume a large amount of clonidine may initially experience high blood pressure, which then drops to low blood pressure. This phenomenon is not well-explained, but it might connect to maximum serum concentrations and baseline sympathetic activity before consumption. Another distinguishing feature is low body temperature that can help differentiate clonidine poisoning from opioid toxicity, where this particular feature is absent.
There are reports that the impact of clonidine can vary based on the dose consumed and the age of the person, although this is not fully established. It’s suggested that heart and breathing problems may only occur with doses greater than 0.01-0.02 mg/kg, while some sources claim toxicity with a dose of only 0.2 mg. Some research indicates that the severity of a slow heart rate consistently depends on the dose, but low blood pressure can vary widely in severity, onset, and duration. Age also plays a role as it affects the sensitivity of specific receptors and decreases the reuptake of a certain neurotransmitter. Elderly patients therefore tend to have higher neurotransmitter concentrations, reducing the effects of clonidine and the doses necessary to cause toxicity. A study on children overdose cases revealed that the age group from 0 to 4 years had a higher incidence of clinical effects compared to the 5 to 8 and 9 to 12 year age groups.
Breathing problems are common in children with clonidine poisoning, and they may need a machine to help them breathe. A serious breathing complication can occur within a few hours of a toxic intake.
Testing for Clonidine Toxicity
Checking the levels of Clonidine in your blood isn’t a useful way to measure the severity of Clonidine toxicity, so doctors won’t typically ask for this test. Instead, your blood will be checked for levels of electrolytes and glucose. They will also screen for conditions like anion gap acidosis (an imbalance in the body’s acids and bases) or hypoglycemia (low blood sugar).
Additional tests that your doctor might consider include:
- 12-lead electrocardiogram: It’s a heart test that checks for problems with the electrical activity of your heart.
- Pregnancy test: For females of reproductive age to rule out pregnancy-related conditions.
- Computed tomography (CT) scan: A type of imaging that uses X-rays to create detailed pictures of inside the body.
- Magnetic resonance imaging (MRI) scan: This test uses a magnetic field and radio waves to create images of the body’s organs and structures.
- Lumbar puncture: A procedure in which fluid is extracted from the spine in the lower back to test for infections or diseases.
Treatment Options for Clonidine Toxicity
In most cases, adults and children who overdose on clonidine, a medication mainly used to treat high blood pressure, don’t experience severe symptoms that require major medical intervention. Serious consequences like death or the necessity for procedures such as intubation or use of drugs that enhance heart function are rare and generally only occur under extreme circumstances, like very young age or extremely large dosage. In studies of adults who overdosed on clonidine, a slower heart rate was the most typical result, lasting roughly one to two days after consuming the medication.
Given that severe poisoning needing immediate, high-level medical attention is rare, the main approach to managing clonidine overdoses is supportive care. If the person’s blood pressure drops severely (hypotension), the first response should be to administer fluids. If this doesn’t work, medications that enhance the heart function (pressors) are recommended. Specific drugs used might include dopamine or norepinephrine, but no studies indicate that one is superior to the other. In some instances, a person might need to be intubated – have a tube placed in their windpipe to assist with breathing – particularly if their breathing has become dangerously slow.
There’s been ongoing debate about using naloxone, a drug frequently used to counteract opioid overdoses, to treat clonidine overdoses. The concept comes from the thought that naloxone might reverse the effect of natural opioids released in the body due to clonidine poisoning. However, whether naloxone will be effective depends on a range of factors, including the person’s initial blood pressure and other bodily responses prior to consuming the medication. Despite varying outcomes in different studies and reports, many sources recommend cautious use of naloxone if the person is struggling to protect their airway, given that side effects are rare. Typically, the dosage would gradually increase from 0.1 mg to 10 mg.
Using atropine to speed up a slow heart rate has also been proposed, but results are inconsistent. In some cases, a device to control heart pacing might be necessary if the person’s heart rate is slow and they’re physically unstable, but there’s no solid evidence to support this.
In general, if a person who has consumed too much clonidine doesn’t exhibit any signs of toxicity within a few hours, they might be discharged from the hospital after being monitored for a period of between four to eight hours. Unless other substances have also been consumed, adults who overdose on clonidine won’t usually need to be admitted to the ICU as delayed effects are uncommon. Even adults who only exhibit a slower heart rate could be discharged at times. However, any child presenting with heart-related or central nervous system symptoms should be admitted to a pediatric ICU.
What else can Clonidine Toxicity be?
- Alcohol poisoning
- Overdose of calming or sleeping medication
- Disruption of salt and mineral balance in the body (excessive calcium or sodium)
- Meningitis (an infection causing inflammation of the brain and spinal cord membranes)
- Reye’s syndrome (a rare but serious condition that causes swelling in the liver and brain)
- Stroke (a sudden interruption in the brain’s blood supply)
What to expect with Clonidine Toxicity
Clonidine is generally a safe medication, and deaths from taking too much of it are rare. The majority of health problems or deaths related to Clonidine use usually come from difficulties with breathing, not heart-related issues. This medication can also be linked to some issues affecting the central nervous system, for example, depression, and problems with heart and lung functioning. However, if a Clonidine overdose is properly treated, patients typically recover well.
Possible Complications When Diagnosed with Clonidine Toxicity
Clonidine toxicity, or poisoning from the drug Clonidine, can lead to serious health issues. This includes severe apnea, a condition where a person stops breathing temporarily, and respiratory depression, or slow and ineffective breathing. These conditions may be so severe that emergency intervention in the form of endotracheal intubation (putting a tube down a patient’s throat to aid breathing) and mechanical ventilation (a machine that helps with breathing) is needed. On top of these issues, Clonidine toxicity can also result in low blood pressure. There’s also a chance it could lead to bradycardia, a slower than normal heart rate.
Common complications from Clonidine toxicity:
- Severe apnea
- Respiratory depression
- Need for emergency endotracheal intubation and mechanical ventilation
- Low blood pressure
- Bradycardia (slower than normal heart rate)
Preventing Clonidine Toxicity
If someone has intentionally swallowed too much of a substance, it’s important that they meet with a mental health professional. However, if the overdose was accidental, the person should receive advice on how to correctly dose and administer their medications to avoid any future incidents. In cases where a child has taken too much of a substance, it’s often a sign that the child or their parent needs to be better educated on the critical importance of keeping medication out of the child’s reach.
