Introduction
Topmate 50 is a medicine used to treat epilepsy (seizures) and to prevent migraines. It is also used in the treatment of Lennox-Gastaut syndrome (a rare, but severe form of epilepsy that starts in early childhood).
Topmate 50 controls seizures by decreasing the abnormal and excessive activity of the nerve cells in the brain. It may be taken with or without food, preferably at the same time, each day. If you have missed a dose, take it as soon as you remember it and finish the full course of treatment even if you feel better. Stopping the medication suddenly without talking to your doctor may cause increased frequency of seizures. Your doctor may advise regular monitoring of serum bicarbonate levels while you are taking this medicine.
Some of the common side effects of this medicine include nausea, taste change, fatigue, diarrhea, weight loss, loss of appetite, and memory impairment. It may also cause vision problems like myopia or glaucoma, so it is important to get your eyesight checked before you start the treatment and regularly thereafter. You may experience dizziness and sleepiness, so do not drive or do anything that requires mental focus until you know how this medicine affects you. Please consult your doctor if these side effects bother you or do not go away.
Uses of Topmate 50
- Epilepsy/Seizures
- Prevention of migraine
- Lennox–Gastaut syndrome
Side effects of Topmate 50
Common
- Abdominal pain
- Diarrhea
- Dizziness
- Fatigue
- Fever
- Loss of appetite
- Memory impairment
- Nausea
- Nervousness
- Numbness
- Psychomotor impairment
- Sleepiness
- Speech disorder
- Taste change
- Upper respiratory tract infection
- Visual impairment
- Weight loss
How to use Topmate 50
Take this medicine in the dose and duration as advised by your doctor. Swallow it as a whole. Do not chew, crush or break it. Topmate 50 may be taken with or without food, but it is better to take it at a fixed time.
How Topmate 50 works
Topmate 50 is an antiepileptic medication. It controls seizures or fits by decreasing the abnormal and excessive activity of the nerve cells in the brain.
What if you forget to take Topmate 50?
If you miss a dose of Topmate 50, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular schedule. Do not double the dose.
Indication
Epilepsy, Migraine prophylaxis, Seizures associated w/ Lennox-gastaut syndrome
Administration
May be taken with or without food.
Adult Dose
Oral
Partial-Onset or Primary Generalized Tonic-Clonic Seizures
Monotherapy
Adult: 25 mg PO q12hr initially; may increase by 50 mg/day at weekly intervals to 200 mg PO q12hr.
Adjunctive therapy
25-50 mg/day PO initially; increase by 25-50 mg/day at weekly intervals to 100-200 mg q12hr for partial onset seizures and 200 mg q12hr.
Lennox-Gastaut Syndrome
Indicated as adjunctive therapy for seizures associated with Lennox-Gastaut syndrome (LGS)
25-50 mg/day PO initially; increase by 25-50 mg/day at weekly intervals to 100-200 mg q12hr
Migraine Headache
Indicated for prophylaxis of migraine headache
Titrate over 4 wk to achieve a dose of 50 mg PO BID
Week 1: 25 mg PO at night
Week 2: 25 mg PO BID
Week 3: 25 mg PO in the morning and 50 mg at night
Week 4: 50 mg PO BID
Hepatic impairment: Dosage adjustment may be needed.
Child Dose
Oral
Partial-Onset or Primary Generalized Tonic-Clonic Seizures
Monotherapy
<2 years: Safety and efficacy not established
2 to <10 years: 25 mg PO at night for 1 week; titrate dose over 5-7 weeks to target daily maintenance dose (weight based) and divide into q12hr dosing schedule
Weight-based dosing
Up to 11 kg: 150 mg/day minimum; 250 mg/day maximum
12-22 kg: 200 mg/day minimum; 300 mg/day maximum
23-31 kg: 200 mg/day minimum; 350 mg/day maximum
32-38 kg: 250 mg/day minimum; 350 mg/day maximum
>38 kg: 250 mg/day minimum; 400 mg/day maximum
>10 years
25 mg PO q12hr initially
Titrate by increments of 50 mg/week up to 200 mg q12hr
Adjunctive therapy
<2 years: Safety and efficacy not established
2-16 years: 25 mg PO qHS(once at night) initially for first week (based on 1-3 mg/kg/day); increase dose by 1-3 mg/kg/day PO divided q12hr at 1-2 week intervals to 5-9 mg/kg/day divided q12hr
>17 years: 25-50 mg/day PO initially; increase by 25-50 mg/day at weekly intervals to 100-200 mg q12hr for partial onset seizures and 200 mg q12hr for generalized tonic/clonic seizures
Lennox-Gastaut Syndrome
Adjunctive therapy
<2 years: Safety and efficacy not established
2-16 years: 25 mg PO qHS initially for first week (based on 1-3 mg/kg/day); increase dose by 1-3 mg/kg/day PO divided q12hr at 1-2 week intervals to 5-9 mg/kg/day divided q12hr
>17 years: 25-50 mg/day PO initially; increase by 25-50 mg/day at weekly intervals to 100-200 mg q12hr for partial onset seizures and 200 mg q12hr for generalized tonic/clonic seizures
Migraine Headache
Indicated for prophylaxis of migraine headache
<12 years: Safety and efficacy not established
Guide dose/titration rate by clinical outcome; if needed, use longer intervals between dose adjustments
>12 years
Titrate over 4 wk to achieve a dose of 50 mg PO BID
Week 1: 25 mg PO qHS(once at night)
Week 2: 25 mg PO BID
Week 3: 25 mg PO in the morning and 50 mg HS
Week 4: 50 mg PO BID
Renal Dose
Renal impairment: Moderate to severe: Doses should be halved. Haemodialysis: supplemental dose equal to about ½ of the daily dose should be given in divided doses (at the start and finish of haemodialysis).
Contraindication
Contraindicated in persons showing hypersensitivity to any component of this preparation.
Mode of Action
Topiramate is a sulfamate-substituted monosaccharide with precise mechanism of action unknown. It may be due to various mechanisms e.g. blocking of voltage-dependent sodium channels; augmenting the activity of ?-aminobutyric acid (GABA) at GABA-A receptor; antagonising AMPA/kainate glutamate receptors; inhibiting carbonic anhydrase.
Precaution
Renal or hepatic impairment, pregnancy, lactation. May impair ability to drive or operate machinery. Maintain adequate hydration to reduce the risk of renal calculi especially in predisposed patients. Measure serum bicarbonate at baseline and periodically during treatment. Avoid abrupt withdrawal; decrease dose by 100 mg daily at wkly intervals. Seek immediate medical attention if blurred vision or eye pain. Monitor closely for decreased sweating and increased body temperature, especially in hot weather. Ensure proper hydration before and during activities or exposure to warm temperatures.
Lactation: Excreted in milk; use caution
Side Effect
>10%
Decrease in serum bicarbonate (7-67%),Dizziness (4-29%),Fatigue (9-16%),Ataxia (6-16%),Nervousness (9-18%),Paresthesia (1-11%),Psychomotor slowing (3-13%),Abnormal vision (2-13%),Anorexia (4-24%),Confusion (4-11%),Decreased memory (2-12%),Nausea (6-10%),Speech disorder (2-13%),Injury (14%)
1-10%
Abdominal pain (6-10%),Weight loss (4-9%),Diplopia (1-10%),Mood problems (<6%),Pharyngitis (6%),Tremor (3-9%),Abnormal gait (3-8%),Apathy (1%),Asthenia (1-5%),Dry mouth (2%),Menorrhagia (1-2%),Skin disorder (2-3%),Taste change (2%),Edema (2%),Hypertension (1-2%),Syncope (1%),Bradycardia (1%),Pallor (1%)
<1%
Angina,Erythema,Hepatic failure,Hyperthermia,Hypokalemia,Neuropathy,Toxic epidermal necrolysis
Interaction
Coadmin with antiepileptic drugs e.g. phenytoin, carbamazepine, phenobarbital decreases plasma concentration of topiramate. Possible increase in phenytoin levels. Increased risk of renal stone formation with carbonic anhydrase inhibitors e.g. acetazolamide. Increased risk of CNS depression with CNS depressants and alcohol. Increased risk of hyperammonaemia and encephalopathy with valproic acid. Increased risk of contraceptive failure in women taking combined oral contraceptives.