Common Adverse Effects of Anti-epileptic Drugs

Common Adverse Effects of Anti-epileptic Drugs

Introduction

Epilepsy is a common condition and it is routinely treated with anti-epileptic drugs (AEDs). It is important to continue AEDs for a long time, even life long in many cases, in order to remain seizure-free. Seizure freedom depends on taking appropriate anti-epileptic drug, at a correct dose and interval, everyday for a long period of time.

When one takes drugs for long time, we need to be aware of the possible side effects. The currently used anti-epileptic drugs have been well studied in clinical trials and data about their safety and possible side effects are well known.

My aim, in this article, is to briefly summarize the common side effects of commonly used AEDs. Early recognition of side effects is important to minimise any harm due to AEDs. 

Side Effects of Phenytoin (Dilantin, Eptoin, etc)

Phenytoin is one of the commonest AED used and also among the oldest drugs. It is used in all age groups.

The main advantage is its availability in injection form; so, it is also used in emergency situations.

The other advantage is that the full dose can be started on day 1 and there is no need to start at low dose and gradually increase the dose (as we need to do with carbamazepine, oxcarbazepine, lamotrigine, etc).

Side effects of phenytoin injection- if injection is rapidly given, it can lead to low blood pressure and cardiac arrest. Also, severe drowsiness can occur.

With the use of phenytoin tablets, the following side effects should be watched for:

• Imbalance while walking,
• blurred vision,
• increased facial hair,
• coarse facies,
• thickening of gum,
• skin rashes. 

Gum hyperplasia due to phenytoin use

Side effects of Carbamazepine (Tegretol, tegrital, mazetol, zeptol, Zen, etc)

Carbamazepine is useful in partial or focal epilepsies and can be used in all age groups. Syrups are available for use in children. However, injection forms are not available, which prevents its use in emergency situations.

Common side effects include:

• Dizziness,
• Drowsiness,
• Imbalance while walking,
• Skin rash,
• Lowering of sodium level (hyponatremia)

The first three side effects can be minimised if carbamazepine is started at a low dose and the dose is gradually increased over a period of days. 

Oxcarbazepine have similar side effects, however, the incidence is lesser than that of carbamazepine. 

Side Effects of Sodium valproate (Depakine, Valparin, Encorate, Valprol, etc)

Sodium valproate is effective in controlling generalised epilepsies, juvenile myoclonic epilepsy (JME), absence seizures, etc. 

Common side effects of valproate include:

• Weight gain,
• Tremors of hands,
• Hair loss,
• Liver toxicity,
• Menstrual irregularities,
• Increased incidence of polycystic ovary disease,
• Pregnancy-related complications.

Sodium valproate should be avoided in patients with liver disease.

Also, it should not be used in women who are pregnant or are planning pregnancy. 

Side Effects of Levetiracetam (Keppra, levipil, levera, etc)

Levetiracetam is a newer AED and is effective in controlling various types of seizures. It is safer than most of the older AEDs. It has injection form, so, it can be used in emergency situations. Also, it is safe in all age groups and can be used in pregnant women too. 

Side effects to be watched for while using levetiracetam are:

• General weakness,
• Sleepiness,
• Aggression and behavioural changes,
• Occasional skin rashes. 

Side Effects of Lamotrigine (Lamictal, lamitor, lametec, etc)

Lamotrigine is also very effective AED, and can be safely used in children as well as pregnant women. 

Side effect to be watched for with lamotrigine use are: 

• Nausea, vomiting, 
• dizziness,
• sleepiness,
• imbalance while walking,
• skin rash

The dose of lamotrigine should be very gradually increased to avoid skin rash.

I hope you find this article useful. Feel free to contact me at the details below. 

Dr Sudhir Kumar MD (Medicine), DM (Neurology)

Senior Consultant Neurologist

Apollo Hospitals, Hyderabad, India.

Email: drsudhirkumar@yahoo.com

Phone: 0091-40-23607777 (to fix appointment for consultation)

online consultation: http://bit.ly/Dr-Sudhir-kumar

VERTIGO or DIZZINESS or GIDDINESS

VERTIGO

What is vertigo?

Vertigo is a common symptom in patients presenting to neurology outpatient department. It is described as a sense of rotation (rotation of self or of the surroundings). Other terms to describe the same sensation are dizziness, giddiness, chakkar (in Hindi), tala tiragadam (in Telugu), etc.

What are the common symptoms in a patient with vertigo?

The most common feeling is a sense of rotation or imbalance. This feeling becomes more prominent while walking or moving. In some cases, even head or neck movements (such as getting up from lying down position or bending down to pick something) can aggravate the symptoms of dizziness. Other symptoms may include:

·      Nausea,

·      Vomiting,

·      Imbalance while walking,

·      Blurred vision,

·      Poor concentration.

What are the common causes of vertigo?

Vertigo can be caused by a variety of reasons. The more important of them include:

BPPV- benign paroxysmal positional vertigo

·      In this condition, there is a problem in the inner ear. Calcium crystals get deposited in one of the semicircular canals.

·      It can occur in all ages, and is common in adults and in older people. It affects 2.4% of population sometime in their lifetime.

·      It is a benign condition, which means it is not life-threatening and it does not get worse over time,

·      Symptoms are made worse with head or neck movements (positional symptoms),

·      Symptoms occur intermittently,

·      People may get better in 1-2 days, however, in some, it may last for a few months also,

·      Head injury, concussion, migraine, etc may bring on the symptoms of BPPV

·      Diagnosis is made on the basis of history and clinical examination. Hearing and vestibular tests may be helpful.

·      Treatment consists of symptomatic treatment with antihistaminic medications such as betahistine tablets.

·      Canal repositioning procedures done in office are helpful and can cure the condition, however, these procedures should be done by trained doctors,

·      Vestibular adaptation exercises help in prevention of recurrent episodes of vertigo.

·      In refractory cases, there may be a role for ear surgery. 

2

Posterior circulation stroke (Brain stroke)

·      This refers to reduction in blood supply to the back of brain, mainly cerebellum and brain stem.

·      This is more common in people with risk factors for stroke, such as high blood pressure, diabetes, high cholesterol, smoking, etc.

·      Patients often have additional symptoms such as double vision, slurred speech, difficulty in swallowing, imbalance while walking, etc. Isolated symptoms of vertigo without any additional symptoms, seldom/rarely occur due to brain stroke.

·      The diagnosis can be confirmed by doing an MRI scan of brain.

·      Treatment is done as for brain stroke (refer to my earlier blog articles on brain stroke management).

 Cervical vertigo

·      This is an uncommon cause of vertigo,

·      Occurs in the setting of severe cervical spondylosis and disc disease in the cervical (neck) region,

·      Cervical vertigo is also more common in older people.

·      Treatment is as for disc disease (refer to my earlier article on disc disease)

 Miscellaneous causes of vertigo

In addition to the above listed main causes of vertigo, we should also look for other causes. These include low blood pressure, anemia (low haemoglobin), general weakness, low blood sugars, etc. 

Who should we consult for vertigo?

Initially, a primary care physician may be consulted. If there is a doubt in exact diagnosis, the patient should be evaluated by a neurologist. 

An ENT opinion may be taken if an ear-related cause is suspected.

What is the outcome in cases of vertigo?

Most people with vertigo recover well and they do so in a few days. However, a minority of patients continue to suffer for several months. It is uncommon for the symptoms to last for more than three months.

Vertigo may be disabling in the first few days of illness, however, after that period, most people are able to normally function.

Dr Sudhir Kumar MD (Internal Medicine) DM (Neurology)

Senior Consultant Neurologist

Apollo Hospitals, Jubilee Hills, Hyderabad

Email: drsudhirkumar@yahoo.com

Phone (for appointment): 0091-40-23607777, extension 6634/3011

Online consultation: http://bit.ly/Dr-Sudhir-kumar