Carbamazepine Test

Epilepsy, Bipolar disorder, Alcohol withdrawal

Carbamazepine is a drug that is administered to treat certain seizure disorders, commonly known as epilepsy. It is helpful for patients with bipolar disease to calm their moods, reduce alcohol withdrawal, and relieve some types of nerve pain.

The Carbamazepine test measures the level of this drug in the given blood sample. As the drug has to be within a specific therapeutic range. Carbamazepine levels need constant monitoring.

The drug may not be helpful if the value is too low, and the person may experience a repeat of symptoms (e.g., seizures, mania, or pain). On the other hand, if the level increases, the person may experience hazardous side effects.

For a variety of reasons, maintaining a therapeutic dose of this medicine can be challenging to achieve. One of them is carbamazepine oral dosages which are absorbed at varying rates in the digestive system. Conditions that alter the drug's ability to attach to proteins have an impact on its therapeutic effectiveness. This can happen in case of low blood albumin, kidney failure, or in a newborn or elderly.

Several medicines may interact with carbamazepine and influence the body’s metabolism and blood levels if used together. Carbamazepine doses need careful monitoring to achieve a constant blood concentration, therefore there is a need to perform Carbamazepine tests frequently.

Carbamazepine is used to treat chronic illnesses such as epilepsy, bipolar disorder, trigeminal neuralgia, and diabetic nerve pain. It needs frequent evaluation over time.

Bipolar disorder is a mental illness marked by recurrent episodes of depression and mania that can last days, weeks, months, or even years. Carbamazepine is useful in helping people with bipolar disorder, particularly mania, and in regulating their mood.

Epilepsy is a long-term illness that necessitates ongoing treatment. Globally, 50 million people worldwide have epilepsy, out of which close to 10 million people with epilepsy live in India, accounting for nearly one-sixth of the total. In India, the prevalence of epilepsy ranges from 4.15 to 7.03 per 1000 people.

When compared to other psychiatric illnesses, bipolar disorder has a prevalence of 6.9% in India.

Carbamazepine is a licensed psychiatric drug that manages epilepsy, bipolar disorder, and other psychological disorders. It is used to manage trigeminal neuralgia as well. Diabetic peripheral neuropathic pain, which affects 10-20% of a person’s functionality, mood, and sleep habits, is also regulated by carbamazepine. Therefore, carbamazepine testing has become essential.

Other names of Carbamazepine Test

• Tegretol
• Tegretol-XR
• Carbatrol
• Epitol
• Equetro

What does the carbamazepine test measure, and who is this prescribed for?

A Carbamazepine test procedure may be done by a healthcare professional to assess someone with side effects, adverse reactions, or a return of symptoms. Free carbamazepine or its physiologically active form is ordered together with a Total Carbamazepine test to assess their contribution to a patient's therapy.

Additional Total Carbamazepine tests may be needed if the drug's dosage is to be modified, the patient changes or discontinues medications, or if their effects are assessed on the carbamazepine level.

When a person does not appear to be responding to therapy and has a repetition of symptoms of seizures, nerve pain, or bipolar mood swings, a Carbamazepine test may be essential. It's also possible that the carbamazepine level isn't high enough when the person isn't taking the prescription regularly, or that the treatment is inefficient for that specific condition.

If a patient experiences severe side effects or develops complications, a Carbamazepine test is requested.

In general, the following side effects may occur at any dose but are more likely at higher concentrations:

• Dizziness
• Uncoordinated movement
• Sleepiness
• Blurred or double vision
• Involuntary movements of the eyeballs
• Red, itchy rash
• Nausea
• Diarrhoea
• Constipation
• Headache
• Confusion

The levels of carbamazepine vary depending on age, gender, medical history, alcohol abuse, dose of medication at the time of sample collection, and different techniques of laboratories.

Ideally, a Carbamazepine test value below 12mcg/mL is appropriate for treatment. The symptoms of carbamazepine toxicity develop when the values cross 30 mg/L.

• Therapeutic: 4.0-12.0 mcg/mL
• Critical value: > or = 15.0 mcg/mL
• The minimum toxic level is 10 mg/kg.
• The toxic concentration value is between or greater than 30-40 mg/L.

Carbamazepine has a terminal elimination half-life of 18-55 hours in short-term use and 5-26 hours in long-term use with 3-5 weeks of drug therapy.

When do you check carbamazepine levels?

Carbamazepine levels are checked,

• When toxicity is suspected
• In severe skin and blood reactions
• In patients with mental illness

• Anxiety
• Depression
• Suicidal thoughts
• Feeling agitated
• Restlessness
• Acting aggressive
• Violent behaviour
• Acting on dangerous impulses

What labs are needed for carbamazepine?

In a patient suspected of carbamazepine poisoning, the labs need the following screening as well:

• Blood alcohol levels should be measured if alcohol toxicity is suspected.
• Several serum electrolyte values are to be checked for, such as glucose, calcium, magnesium, phosphate, serum bicarbonate, blood urea nitrogen, and serum creatinine.
• It is advised to perform liver function tests since persistent poisoning can produce high liver enzyme levels, hepatitis, and other liver disorders.

Depending on your age, gender, medical history, test method, and other factors, your Carbamazepine test results may differ.

Total and free carbamazepine levels, like those of other anticonvulsant medications, should be correlated with the patient's clinical status. The Carbamazepine test guide is meant to act as a starting point for dose adjustments.

Micrograms per millilitre (mcg/mL) or micromoles per litre (micromol/L) are the units of measurement.

Carbamazepine blood levels of 4 to 12 mcg/mL, or 17 to 51 micromol/L, are considered safe. If your levels are more than 40 mcg/mL, or 170 micromol/L, you may experience seizures, low blood pressure, or even a coma.

Free carbamazepine levels are greater than 1.0 mcg/mL in individuals with normal renal function, and toxicity can occur when free carbamazepine levels are greater than or equivalent to 4.0 mcg/mL.

The free carbamazepine level, rather than the total level, may be a better reference for dosage modifications in people with renal failure.

The range of 1.0 to 2.0 mcg/mL has been linked to therapeutic-free levels in individuals with severe uremia.

Toxicity can ensue when the free carbamazepine level is more than or equal to 4.0 mcg/mL (even though the total carbamazepine concentration is less than 15.0 mcg/mL).

In general, if Carbamazepine test results are within the therapeutic range and the patient does not have repeated seizures, mood swings, or nerve pain, as well as no serious side effects, carbamazepine dosage is considered appropriate.

The Carbamazepine test results are based on blood sample analysis. A blood sample is collected at a laboratory. Usually, blood is taken from a vein in the arm. This Carbamazepine test doesn’t possess any risk and usually takes place in a short duration. For more specific instructions, consult the concerned doctor.

Test Preparation

A Carbamazepine Test is a blood test that does require fasting for 10-12 hours before sample collection. A blood sample is collected from a vein in the forearm.

The blood sample is analysed further after being sent to the laboratory. It takes only 5 minutes and has no risks. However, you must discuss the timing of the sample collection with your doctor. Carbamazepine is usually taken right before the next dose when the concentration level is lowest.

Carbamazepine test inclusions: What are the parameters included?

This test determines the concentration of carbamazepine present in your blood. A standard carbamazepine test examines total carbamazepine, including both protein-bound and free forms.

The carbamazepine includes three parameters.

• Free Carbamazepine
• Percent Free Carbamazepine        
• Total Carbamazepine

An elevated level of carbamazepine indicates toxicity leading to several complications.

How frequently should you take the Carbamazepine test?

A doctor advises a Carbamazepine test when they suspect any toxicity symptoms. To ensure that therapeutic blood concentrations of carbamazepine are maintained, Carbamazepine tests are ordered often at first.

From time to time, Carbamazepine tests need to be repeated, as per the doctor’s advice.