Individuals with active epilepsy in the US are estimated to be around 1.2 percent of the population accounting for 3.4 million citizens. Prevalence rates of bipolar disorder are pegged higher at 2.8 percent of the total population. Bipolar disorder requires lifelong mediations and individuals with the condition are expected to be on the prescribed treatments at all times, including phases of life when there are no obvious symptoms of the condition. In the case of epilepsy, seizures are not known to occur throughout life for a subset of patients. Depending on the condition, and the occurrence, patients may choose to discontinue medications with consent or recommendations of treating specialists. The following subsections profile a phenyltriazine antiepileptic used in the treatment of the conditions, offering all relevant information including details of the side effects of lamotrigine.

Overview of Lamotrigine

Belonging to the class of phenyltriazine antiepileptic, it is used to treat certain types of epilepsy apart from bipolar I disorder. It helps in stabilizing moods among patients with bipolar disorder and has the distinction of being the second medication to receive FDA approval for managing the condition. The highlight of the medication is its better tolerance and lower side effects, and it is also being studied for managing neuropathic pain.

Mechanism of action of the medication

While the actual mechanism of action of the medication is unclear, it is known to deliver desired outcomes by inhibition of certain sodium channels, and by stabilization of neuronal membranes. This results in regulating the release of certain neurotransmitters. The inhibition of sodium channels is through a selective binding action, that causes a suppression of glutamate, an amino acid. The sequence of action results in anticonvulsant properties that make it effective in treating the conditions. By virtue of working in a manner that is similar to anesthetics, it is the subject of studies to determine efficacy in managing neuropathic pain. Another action or property that is linked to the anticonvulsant effects of the medication is the inhibition of calcium currents.

The ideal dosage of the medication

One of the reasons for undesirable effects of medications, including side effects of Lamotrigine is the effect of incorrect dosage and improper use of the medication. It is important to follow the dosage recommendations diligently and ensure that the schedule is as per the advice of the specialists. Here is some reference information on the average dosages for different conditions. The actual dosage may differ and will depend on various factors such as the intensity of the condition being treated, other existing conditions, medications in use and health, age of the patient. The oral forms of the medication include chewable tablets, disintegrating tablets, and tablets that can be swallowed whole.

Dosage for bipolar disorder

When taken in oral forms, the patient is ideally started off with 25 milligrams daily for a fortnight, which is then increased to 50 milligrams daily for the next fortnight. Depending on the condition and the response of the patient, this may then be increased further, gradually. However, regardless of the condition, the maximum upper limit of the medication does not usually exceed 200 milligrams daily. The dosage listed above is specifically for patients not on certain medications. For instance, this dosage is subject to the condition that patients are not on any of the following:

 

In the case of patients on Valproic acid, the dosage will initially start with 25 milligrams on alternate days for a fortnight, which will then be gradually increased to 25 milligrams daily for the next fortnight. Depending on the condition and the response, the dosage may be increased further, but this does not usually exceed 100 milligrams daily, due to the possibility of interactions with the above medications.

In the case of patients on the other medications listed above, other than Valproic acid, the dosage will initially start with 50 milligrams daily for a fortnight, which will then be gradually increased to 100 milligrams daily for the next fortnight which will be administered in two equal doses. Depending on the condition and the response, the dosage may be increased further, but this does not usually exceed 400 milligrams daily, due to the possibility of interactions with the above medications.

Dosage for epilepsy

In the case of patients on Carbamazepine, Phenobarbital, Phenytoin, or Primidone and not on Valproic acid, the dosage will initially start with 50 milligrams daily for a fortnight, which will then be gradually increased to 100 milligrams daily for the next fortnight which will be administered in two equal doses. Depending on the condition and the response, the dosage may be increased further, but this does not usually exceed 500 milligrams daily.

Patients not on Valproic acid, Carbamazepine, Phenobarbital, Phenytoin, or Primidone are typically started off on a dosage of 25 milligrams daily for a fortnight, which is then increased to 50 milligrams daily for the next fortnight. Depending on the condition and the response of the patient, this may then be increased gradually, subject to a maximum dosage of 375 milligrams daily.

Patients on Valproic acid and not on other medications are typically recommended a dosage of 25 milligrams on alternate days for a fortnight, which is then increased to 25 milligrams daily for the next fortnight. Depending on the condition and the response of the patient, this may then be increased gradually, subject to a maximum dosage of 400 milligrams daily.

The actual dosage for children may depend on the conditions, and other medications used in treatment. The dosage for extended-release formulations also differs from that of the dosage mentioned above.

Precautions that need to be in place to prevent or mitigate side effects of lamotrigine

Pregnant women are expected to intimate doctors when on the medication, and women are advised to seek medical advice before commencing or discontinuing birth control pills or any other hormonal replacement therapy. Patients, especially children need to be periodically monitored to check the progress of the medication and or manifestations of undesirable outcomes. Women are also advised to monitor their menstruation cycle when on the medication. Other precautions include:

Commonly reported undesirable effects or outcomes of Lamotrigine

The medication, despite its relatively lesser side effects, does not entirely rule out the possibility of unwanted outcomes. For instance, individuals may experience vision-related challenges or changes such as blurring of vision, dizzy feelings, or unsteady movements. There is also the possibility of patients experiencing an outbreak of rashes on the skin. This may begin as a small or trivial allergy or rash, but could quickly turn into a serious condition. Serious or adverse outcomes from the medication include a life-endangering disorder – an excessive production of macrophages, and lymphocytes. Medically known as hemophagocytic lymphohistiocytosis, the over-activated immune cells can be serious and require urgent medical intervention.

Allergic symptoms that require urgent medical attention

Certain allergic reactions require urgent medical attention, to prevent the condition from turning serious in nature. For instance, there could be an impact on vital organs of the body such as the liver, kidneys, or limbs. Discernible symptoms that indicate possible allergic reactions include low-grade fever, discoloration of urine, throbbing headache, and allergies similar to hives. Other symptoms include pain in the muscles, stiffness in the muscles, stomach pain, and fatigue.

Abnormal behavior and the need for monitoring the patient

There is a possibility of the medication triggering slightly abnormal behavior. For instance, the patient may appear constantly agitated, or easily irritated. There is also the possibility of patients exhibiting suicidal tendencies, apart from depression.  Certain tell-tale symptoms are indicative of Aseptic meningitis and need to be monitored. For instance, children who appear confused, or running a low-grade fever, with headaches need to be assessed by a physician. Other symptoms include a stiff neck, feelings of nausea, or any form of sensitivity to light.

Possible drug interactions

There is the possibility of drug interactions with other medications and patients are advised to consult respective specialists before commencing the medication. Depending on the possible known interaction, the patient may be recommended to either modify the dosage, alter the schedule or stop either of the medications causing the interactions. Some of the drugs that may interact with Lamotrigine include Atazanavir, Cenobamate, Lopinavir, and Rifampin. This is not a comprehensive or exhaustive list of medications, but only a reference of the class of medications that may interact with the drug. The list also includes drugs such as Desogestrel, Ethinyl Estradiol, Ginseng, Nomegestrol, Ritonavir, and Sertraline among others.

High-risk patients

Certain categories of patients may be at higher risk of undesirable effects when compared with other individuals. It is, therefore, necessary for individuals to be aware of the conditions and take suitable preventive and remedial measures. For instance, patients with blood/bone marrow issues, and with a history of cardiovascular complications are to seek a proper assessment before taking the medication. This could include patients who have had a heart attack in the past or are on medications to manage heart issues. Patients with diagnosed depression are also advised to seek advice before commencing the medication. Similarly, patients with existing kidney-related problems or age-related renal impairment are to seek specific recommendations before taking Lamotrigine. This also applies to patients with liver ailments, as this may affect the ability of the body to process the drug.

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