Valex-CR
Generic Name
Valproic Acid Controlled Release
Manufacturer
Square Pharmaceuticals Ltd.
Country
Bangladesh
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Price Details
Current market pricing information
| Variant | Unit Price | Strip Price |
|---|---|---|
| valex cr 200 mg tablet | ৳ 6.00 | ৳ 60.00 |
Description
Overview of the medicine
Valex-CR 200 mg tablet contains Valproic Acid, which is an antiepileptic drug. It is primarily used to treat various types of seizures, control manic episodes associated with bipolar disorder, and prevent migraine headaches. The controlled-release formulation ensures a sustained therapeutic effect over an extended period.
Uses & Indications
Dosage
Adults
Initial dose typically 250 mg twice daily (or as a single daily dose for CR formulation), gradually increased over several weeks to achieve optimal clinical response, usually ranging from 1000 mg to 2500 mg per day. Dosage must be individualized based on patient tolerance and therapeutic response.
Elderly
Start with lower doses and titrate slowly. Monitor for side effects and plasma concentrations closely, as the elderly may be more susceptible to adverse reactions.
Renal_impairment
Generally, no dosage adjustment is required in patients with renal impairment, but careful monitoring is advised. Protein binding may be reduced, increasing free drug levels.
How to Take
Administer orally. Tablets should be swallowed whole; do not crush, chew, or break, as this can affect the controlled-release properties and lead to rapid release of the drug. Can be taken with food to minimize gastrointestinal irritation.
Mechanism of Action
Valproic Acid's exact mechanism of action is not fully understood but is believed to involve increasing brain levels of gamma-aminobutyric acid (GABA), blocking voltage-gated sodium channels, and modulating T-type calcium channels. These actions contribute to its anticonvulsant and mood-stabilizing effects.
Pharmacokinetics
Onset
Anticonvulsant effects may begin within days, but full therapeutic effect can take several weeks for epilepsy and bipolar disorder.
Excretion
Mainly excreted in urine as metabolites, with a small portion excreted unchanged in feces.
Half life
Approximately 9 to 16 hours in adults, varying with age and concurrent medications.
Absorption
Well absorbed orally; controlled-release formulation provides sustained absorption. Peak plasma concentrations are typically reached 2-8 hours post-dose.
Metabolism
Extensively metabolized in the liver, primarily via glucuronidation and mitochondrial beta-oxidation.
Side Effects
Contraindications
- Hypersensitivity to valproate or any component of the formulation
- Severe hepatic dysfunction or active liver disease
- Known urea cycle disorders
- Known mitochondrial disorders caused by mutations in mitochondrial DNA polymerase gamma (POLG), e.g., Alpers-Huttenlocher syndrome, especially in children under 2 years of age
- Porphyria
Drug Interactions
Warfarin
May enhance the anticoagulant effect of warfarin.
Lamotrigine
Valproate can increase lamotrigine levels, leading to a higher risk of serious rash (e.g., Stevens-Johnson syndrome).
Phenytoin, Phenobarbital, Carbamazepine
May alter valproate levels and increase the risk of side effects from these concomitant drugs. Valproate can also increase levels of phenobarbital and phenytoin.
Carbapenem antibiotics (e.g., Meropenem)
Can significantly decrease valproate plasma levels, potentially leading to loss of seizure control.
Storage
Store in a cool, dry place below 30°C. Protect from light and moisture. Keep out of reach of children.
Overdose
Symptoms of overdose include somnolence, heart block, respiratory depression, and coma. Management involves immediate gastric lavage or induction of emesis, followed by activated charcoal. Supportive care, including monitoring vital signs and managing symptoms, is crucial. Naloxone may be used to reverse CNS depression. Hemodialysis or hemoperfusion can be considered for severe cases.
Pregnancy & Lactation
Valproic Acid is highly teratogenic and associated with a high risk of birth defects (e.g., neural tube defects, developmental delays, fetal valproate syndrome). It should be avoided during pregnancy, especially in the first trimester, unless there are no suitable alternatives and the benefits clearly outweigh the risks. Women of childbearing potential should use effective contraception. It passes into breast milk; caution is advised, and consultation with a doctor is necessary.
Side Effects
Contraindications
- Hypersensitivity to valproate or any component of the formulation
- Severe hepatic dysfunction or active liver disease
- Known urea cycle disorders
- Known mitochondrial disorders caused by mutations in mitochondrial DNA polymerase gamma (POLG), e.g., Alpers-Huttenlocher syndrome, especially in children under 2 years of age
- Porphyria
Drug Interactions
Warfarin
May enhance the anticoagulant effect of warfarin.
Lamotrigine
Valproate can increase lamotrigine levels, leading to a higher risk of serious rash (e.g., Stevens-Johnson syndrome).
Phenytoin, Phenobarbital, Carbamazepine
May alter valproate levels and increase the risk of side effects from these concomitant drugs. Valproate can also increase levels of phenobarbital and phenytoin.
Carbapenem antibiotics (e.g., Meropenem)
Can significantly decrease valproate plasma levels, potentially leading to loss of seizure control.
Storage
Store in a cool, dry place below 30°C. Protect from light and moisture. Keep out of reach of children.
Overdose
Symptoms of overdose include somnolence, heart block, respiratory depression, and coma. Management involves immediate gastric lavage or induction of emesis, followed by activated charcoal. Supportive care, including monitoring vital signs and managing symptoms, is crucial. Naloxone may be used to reverse CNS depression. Hemodialysis or hemoperfusion can be considered for severe cases.
Pregnancy & Lactation
Valproic Acid is highly teratogenic and associated with a high risk of birth defects (e.g., neural tube defects, developmental delays, fetal valproate syndrome). It should be avoided during pregnancy, especially in the first trimester, unless there are no suitable alternatives and the benefits clearly outweigh the risks. Women of childbearing potential should use effective contraception. It passes into breast milk; caution is advised, and consultation with a doctor is necessary.
Frequently Asked Questions
Common questions about this medicine
Pack Sizes
Shelf Life
24 months from manufacturing date
Availability
Available in pharmacies and hospitals
Approval Status
DGDA Approved
Patent Status
Generic
WHO Essential Medicine
YesClinical Trials
Valproic acid has been extensively studied in numerous clinical trials for its efficacy in treating epilepsy, bipolar disorder, and migraine prophylaxis, demonstrating significant benefits across these indications.
Lab Monitoring
- Liver function tests (baseline and periodically, especially during the first 6 months of therapy)
- Complete blood count with platelets (baseline and periodically)
- Valproate plasma levels (therapeutic drug monitoring to ensure adequate levels and avoid toxicity)
- Ammonia levels (if symptoms of encephalopathy occur)
Doctor Notes
- Emphasize the importance of patient counseling, especially for women of childbearing potential, regarding the significant teratogenic risks.
- Regularly monitor liver function tests (LFTs) and complete blood counts (CBCs) due to the risk of hepatotoxicity and hematological abnormalities.
- Advise patients not to discontinue the medication abruptly to avoid rebound seizures or worsening of symptoms.
Patient Guidelines
- Take Valex-CR exactly as prescribed by your doctor; do not change the dose or stop taking it without consultation.
- Swallow tablets whole; do not crush, chew, or break them.
- Report any unusual bruising, bleeding, or signs of liver problems (e.g., yellow skin/eyes, dark urine) or pancreatitis (e.g., severe abdominal pain, nausea, vomiting) to your doctor immediately.
- Women of childbearing potential should discuss pregnancy risks with their doctor and use effective contraception.
Missed Dose Advice
If a dose is missed, take it as soon as you remember, unless it is almost time for your next scheduled dose. In that case, skip the missed dose and resume your regular dosing schedule. Do not take a double dose to make up for a missed one.
Driving Precautions
Valex-CR may cause drowsiness, dizziness, or impaired coordination, especially at the beginning of treatment or after a dose increase. Avoid driving or operating heavy machinery until you know how this medication affects you and you are certain you can perform these activities safely.
Lifestyle Advice
- Avoid alcohol while on this medication, as it can worsen side effects and seizure control.
- Maintain a healthy lifestyle, including a balanced diet and regular exercise, which can contribute to overall well-being and potentially help manage weight gain.
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