Absenor (Sodium Valproate)
Antiepileptic medication for epilepsy and bipolar disorder
Quick Facts About Absenor
Key Takeaways About Absenor
- Broad-spectrum antiepileptic: Effective for multiple seizure types including generalized and focal epilepsy, as well as manic episodes in bipolar disorder
- Serious pregnancy risks: Can cause birth defects in approximately 11% of exposed pregnancies and neurodevelopmental problems in 30–40% of children – effective contraception is mandatory
- Regular monitoring required: Blood tests for liver function, pancreatic enzymes, and platelet count are essential, especially during the first months of treatment
- Multiple drug interactions: Interacts significantly with many medications including other antiepileptics, warfarin, aspirin, and carbapenem antibiotics
- Never stop abruptly: Sudden discontinuation can trigger breakthrough seizures or status epilepticus – always taper gradually under medical supervision
What Is Absenor and What Is It Used For?
Absenor is a prescription antiepileptic medication containing sodium valproate. It is used to treat various forms of epilepsy and manic episodes in bipolar disorder. Absenor works by increasing levels of gamma-aminobutyric acid (GABA) in the brain, which reduces abnormal electrical activity and prevents seizures and mood instability.
Sodium valproate, the active ingredient in Absenor, is one of the most widely used antiepileptic drugs worldwide. It was first approved for medical use in the 1960s in France and has since become a cornerstone of epilepsy treatment globally. The World Health Organization includes valproic acid on its List of Essential Medicines, recognizing its critical importance in healthcare systems worldwide.
Absenor is classified as a broad-spectrum antiepileptic drug (AED), meaning it is effective against multiple types of seizures. This makes it particularly valuable for patients who experience different seizure types or when the exact seizure classification is uncertain. Unlike many newer antiepileptic drugs that work through a single mechanism, sodium valproate affects several neurochemical pathways simultaneously.
The medication is available in two main formulations: prolonged-release tablets (Absenor Depot), which release the active ingredient slowly over time for more stable blood levels, and enteric-coated tablets, which have a protective coating that prevents the tablet from dissolving until it reaches the intestine, thereby reducing stomach side effects. Both formulations must be swallowed whole and not crushed or chewed.
Approved Indications
- Epilepsy: Various types of generalized seizures (including absence seizures, myoclonic seizures, tonic-clonic seizures) and focal (partial) seizures with or without secondary generalization
- Manic episodes in bipolar disorder: Treatment of acute manic episodes when lithium is contraindicated or not tolerated
- Maintenance therapy for bipolar disorder: Prevention of recurrent mood episodes in patients who have responded to valproate for acute mania and who cannot use lithium
How Does Absenor Work?
The exact mechanism of action of sodium valproate is not fully understood, but research suggests it works through several complementary pathways. The primary mechanism involves increasing the concentration of GABA, the brain's main inhibitory neurotransmitter, by inhibiting GABA-degrading enzymes and enhancing GABA synthesis. This increased GABAergic activity dampens excessive neuronal firing that leads to seizures.
Additionally, sodium valproate blocks voltage-dependent sodium channels and modulates T-type calcium channels, both of which contribute to its broad-spectrum anticonvulsant activity. For bipolar disorder, its mood-stabilizing properties are thought to be related to effects on intracellular signaling cascades, including inhibition of glycogen synthase kinase-3 (GSK-3) and modulation of protein kinase C activity. These mechanisms help stabilize neuronal membranes and prevent the rapid mood cycling characteristic of bipolar disorder.
What Should You Know Before Taking Absenor?
Before starting Absenor, your doctor must evaluate your liver function, check for metabolic disorders, and discuss pregnancy risks. Absenor is contraindicated in patients with liver disease, porphyria, urea cycle disorders, untreated carnitine deficiency, and Alpers-Huttenlocher syndrome. Women of childbearing potential must use effective contraception throughout treatment.
Contraindications
Absenor must not be taken in the following situations, as use could be dangerous or life-threatening:
- Allergy to sodium valproate or any of the other ingredients in the medication
- Allergy to peanuts or soy (applies to Absenor Depot prolonged-release tablets, which contain soy lecithin)
- Active liver disease or impaired liver function, as valproate is extensively metabolized by the liver and can cause severe hepatotoxicity
- Porphyria (a group of disorders involving abnormal accumulation of certain blood pigments)
- Known mitochondrial disorders caused by mutations in the mitochondrial DNA polymerase gamma (POLG) gene, including Alpers-Huttenlocher syndrome, as these patients have a significantly increased risk of fatal liver failure
- Known urea cycle disorders, as valproate may cause severe hyperammonemia in these patients
- Untreated carnitine deficiency (a very rare metabolic disorder)
For bipolar disorder: Absenor must NOT be used during pregnancy. Women of childbearing potential must use effective contraception throughout treatment.
For epilepsy: Absenor must NOT be used during pregnancy unless no other treatment is effective. Women of childbearing potential must use effective contraception throughout treatment.
Valproate causes birth defects in approximately 11 out of 100 exposed pregnancies (compared to 2–3 per 100 in the general population) and neurodevelopmental disorders in up to 30–40% of exposed children, including reduced IQ, autism spectrum disorder, and ADHD.
Warnings and Precautions
Treatment with Absenor requires careful medical supervision. Discuss the following conditions with your doctor before starting treatment:
- Family history of mitochondrial disorders: If mitochondrial disease is known or suspected in your family, genetic testing for POLG mutations should be performed before starting valproate, as these patients are at high risk of acute liver failure
- Suspected metabolic diseases: Particularly inherited enzyme deficiency disorders such as urea cycle disorders, as these increase the risk of dangerous ammonia accumulation in the blood (hyperammonemia)
- Carnitine palmitoyltransferase (CPT) type II deficiency: This rare condition is associated with an increased risk of rhabdomyolysis (severe muscle breakdown) when taking valproate
- Insufficient carnitine intake: Patients who do not get enough carnitine from their diet (found in meat and dairy products), especially children under 10 years of age, may be at increased risk of side effects
- History of severe skin reactions: If you have previously experienced severe skin rashes, skin peeling, blisters, or mouth sores after taking valproate, inform your doctor immediately
Treatment with Absenor requires regular blood tests to monitor liver function, pancreatic function, and platelet count. These tests are particularly important during the first 6 months of treatment and before any surgical procedures. Attend all scheduled appointments.
Suicidal thoughts: A small number of people treated with antiepileptic medications, including valproate, have had thoughts of self-harm or suicide. If you experience such thoughts at any time, contact your doctor immediately or seek emergency medical attention.
Severe skin reactions: Serious and potentially life-threatening skin conditions including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), drug reaction with eosinophilia and systemic symptoms (DRESS), and angioedema have been reported with valproate treatment. Seek immediate medical attention if you develop widespread skin rash, blistering, peeling, or painful sores in the mouth or eyes.
Liver and pancreas damage: Contact your doctor immediately if you experience loss of appetite, nausea, drowsiness, and tiredness (sometimes with repeated vomiting or stomach pain), jaundice (yellowing of the skin or eyes), swelling of the legs or feet, or sudden worsening of seizure control. These may be signs of serious liver or pancreatic injury, which can be fatal. This risk is highest in infants and children under 3 years with severe epilepsy, especially those with brain damage, intellectual disability, genetic conditions, or who are taking multiple antiepileptic drugs.
Hyperammonemia: Tell your doctor immediately if you or your child develops balance or coordination problems, unusual drowsiness, reduced consciousness, or vomiting. These symptoms may indicate elevated ammonia levels in the blood.
Weight gain: There is a risk of weight gain when taking Absenor. Contact your doctor if you need help managing your weight during treatment.
Do not stop abruptly: You should never stop taking Absenor suddenly, as this can increase the risk of seizures, potentially including status epilepticus (a prolonged, life-threatening seizure). Any dose changes must be made gradually under medical supervision.
Pregnancy and Breastfeeding
Sodium valproate poses significant risks when used during pregnancy. This section provides critical information for women of childbearing potential and their partners.
Risks During Pregnancy
Valproate is a known teratogen – a substance that can cause birth defects. The risks are significant regardless of the dose used and include:
- Birth defects (in approximately 11% of exposed pregnancies): The most commonly reported defects include spina bifida (incomplete closure of the spine), facial and skull malformations, heart defects, kidney and urinary tract malformations, genital malformations, and limb defects. These birth defects can result in serious disability.
- Hearing problems or deafness have been reported in children exposed to valproate in the womb
- Eye malformations have been reported alongside other congenital abnormalities in exposed children and may affect vision
- Neurodevelopmental disorders (in up to 30–40% of exposed children): Children whose mothers took valproate during pregnancy may experience delayed walking and talking, lower intellectual ability, language and memory difficulties. Autism spectrum disorder and ADHD are diagnosed more frequently in these children.
Requirements for Women of Childbearing Potential
- Pregnancy must be excluded with a pregnancy test before starting treatment
- Effective contraception must be used without interruption throughout treatment
- Annual specialist reviews are required to reassess the need for valproate therapy
- If planning pregnancy, discuss alternative treatments with your specialist before stopping contraception
- If you become pregnant while taking Absenor, contact your doctor immediately – do not stop taking the medication without medical advice
- Folic acid supplementation may reduce the general risk of neural tube defects but is unlikely to reduce the specific risks associated with valproate exposure
Information for Male Patients
A study suggests a possible risk of neurodevelopmental disorders in children whose fathers were treated with valproate within 3 months before conception. In this study, approximately 5 out of 100 children whose fathers took valproate had such disorders, compared to approximately 3 out of 100 children whose fathers took other antiepileptic medications. As a precautionary measure:
- Discuss the potential risks with your doctor
- Use effective contraception (both you and your partner) during treatment and for 3 months after stopping
- Do not donate sperm while taking valproate and for 3 months after stopping
- Inform your doctor if you are planning to father a child
Breastfeeding
Valproate passes into breast milk. The decision to breastfeed should be made in consultation with your doctor, who will weigh the benefits of breastfeeding against the potential risks to the infant. The amount transferred through breast milk is generally considered low (1–10% of maternal serum concentration), and many international guidelines consider breastfeeding acceptable during valproate monotherapy, provided the infant is monitored.
Fertility
Absenor may reduce fertility in both men and women. In men, valproate can affect sperm quality and count. In women, it has been associated with polycystic ovaries and menstrual irregularities. Available evidence suggests that fertility typically returns to normal when treatment with Absenor is discontinued.
How Does Absenor Interact with Other Drugs?
Absenor has significant interactions with many commonly used medications. Carbapenem antibiotics can dramatically reduce valproate levels, potentially triggering seizures. Valproate increases lamotrigine levels (raising toxicity risk) and has complex mutual interactions with carbamazepine, phenytoin, and phenobarbital. Always inform your doctor about all medications you are taking.
Sodium valproate is extensively metabolized by the liver and is highly protein-bound (80–90%), which creates the potential for significant pharmacokinetic interactions with many other drugs. Both the metabolism and protein binding of valproate can be affected by co-administered medications, and valproate itself can alter the metabolism and protein binding of other drugs. Understanding these interactions is crucial for safe and effective treatment.
Major Interactions
| Drug / Class | Effect | Clinical Significance |
|---|---|---|
| Carbapenem antibiotics (ertapenem, imipenem, meropenem) | Can reduce valproate levels by 60–100% within 2 days | May trigger breakthrough seizures; avoid combination if possible |
| Lamotrigine | Valproate inhibits lamotrigine metabolism, doubling its half-life | Increased risk of serious skin reactions (SJS/TEN); lamotrigine dose must be reduced |
| Carbamazepine | Carbamazepine reduces valproate levels; valproate may increase carbamazepine toxicity | Monitor levels of both drugs; watch for signs of toxicity |
| Phenytoin | Complex mutual interaction; free phenytoin levels may increase while total levels appear normal | Monitor free phenytoin levels; watch for toxicity signs |
| Phenobarbital / Primidone | Valproate inhibits phenobarbital metabolism; phenobarbital induces valproate metabolism | Risk of excessive sedation; monitor both drug levels |
| Warfarin | Valproate may displace warfarin from protein binding and affect its metabolism | Monitor INR closely; dose adjustment may be needed |
| Aspirin (Acetylsalicylic acid) | Aspirin displaces valproate from protein binding and inhibits its metabolism | Significant increase in free valproate levels; avoid in children under 3 |
Other Notable Interactions
| Drug / Class | Effect | Action Required |
|---|---|---|
| Topiramate | Increased risk of hyperammonemia and encephalopathy | Monitor ammonia levels; watch for confusion, lethargy |
| Cannabidiol (CBD) | Cannabidiol may increase valproate levels and risk of liver toxicity | Monitor liver function tests closely |
| Felbamate | Increases valproate levels by up to 50% | Reduce valproate dose when adding felbamate |
| Rifampicin | May reduce valproate levels through enzyme induction | Monitor valproate levels; dose increase may be needed |
| Propofol (anesthetic) | Mutual potentiation; increased sedation | Inform anesthesiologist before any procedure |
| Lorazepam | Valproate may increase lorazepam levels | Monitor for excessive sedation; reduce lorazepam dose if needed |
| Mefloquine (antimalarial) | Mefloquine may reduce valproate levels; mefloquine is also epileptogenic | Avoid combination; risk of breakthrough seizures |
| Metamizole | May reduce valproate serum levels | Monitor valproate levels if used concurrently |
| Estrogen-containing products (including some oral contraceptives) | Estrogens may reduce valproate levels | Monitor valproate levels; Absenor is not expected to reduce contraceptive efficacy |
Absenor enhances the effects of alcohol. Avoid consuming alcohol during treatment, as the combination can cause excessive drowsiness, impaired coordination, and reduced alertness, potentially leading to dangerous situations.
What Is the Correct Dosage of Absenor?
The dose of Absenor is individualized based on age, body weight, and the condition being treated. For epilepsy, the usual maintenance dose is 20–30 mg/kg body weight per day. For bipolar disorder (mania), the recommended starting dose is 750 mg per day, with a usual maintenance dose of 1,000–2,000 mg per day. Always follow your doctor's specific instructions.
Dosing of sodium valproate is highly individualized. Your doctor will determine the most appropriate dose based on your specific condition, body weight, response to treatment, and other medications you may be taking. Blood level monitoring (therapeutic drug monitoring) is often used to guide dosage adjustments and ensure levels remain within the therapeutic range, typically 50–100 mg/L (350–700 micromol/L) for epilepsy.
Adults – Epilepsy
Prolonged-Release Tablets (Absenor Depot)
Usual maintenance dose: 20–30 mg/kg body weight per day
Typical daily dose: 1,200–2,100 mg (4–7 tablets of 300 mg), divided into 1–2 doses per day
The prolonged-release formulation allows for once- or twice-daily dosing due to its extended absorption profile, which provides more stable blood levels throughout the day.
Enteric-Coated Tablets
Starting dose: 300 mg three times daily
Dose escalation: Gradually increase until seizures are adequately controlled
Usual maintenance dose: 20–30 mg/kg body weight per day, divided into 2–3 doses
Children – Epilepsy
Pediatric Dosing
Prolonged-release tablets: Approximately 30 mg/kg body weight per day (where appropriate formulation is available)
Enteric-coated tablets: Starting dose of 20–40 mg/kg body weight per day, divided into 2–3 doses, with gradual increases as needed
Important: Absenor must not be used in children and adolescents under 18 years for the treatment of mania or bipolar disorder. Children under 3 years with severe epilepsy, brain damage, developmental delay, or genetic/metabolic conditions require particularly careful monitoring due to higher risk of liver toxicity.
Adults – Bipolar Disorder (Mania)
Manic Episodes
Starting dose: 750 mg per day
Usual maintenance dose: 1,000–2,000 mg per day
The daily dose should be established and monitored individually by your doctor. Dose adjustments are made based on clinical response and tolerability.
Special Populations
Patients with kidney problems: Your doctor may need to adjust your dose, as reduced kidney function can affect the protein binding of valproate, leading to higher free drug levels even when total levels appear normal.
Elderly patients: Lower doses may be needed due to changes in pharmacokinetics with aging, including reduced liver function and altered protein binding. Elderly patients should be monitored more closely for side effects, particularly sedation and tremor.
Missed Dose
If you forget to take a dose, take it as soon as you remember. However, if it is almost time for your next scheduled dose, skip the missed dose and continue with your regular dosing schedule. Never take a double dose to make up for a missed one, as this increases the risk of side effects and potential toxicity.
Overdose
If you or someone else has taken too much Absenor, contact emergency medical services immediately. Signs of acute massive overdose typically include coma with decreased muscle tone, weak reflexes, constricted pupils, respiratory depression, metabolic acidosis, low blood pressure, and cardiovascular collapse. There is no specific antidote for valproate overdose; treatment is supportive and may include hemodialysis in severe cases.
What Are the Side Effects of Absenor?
Like all medications, Absenor can cause side effects, though not everyone experiences them. The most common side effects are tremor and nausea (affecting more than 1 in 10 people). Common side effects include stomach problems, temporary hair loss, weight gain, dizziness, and drowsiness. Serious but rare side effects include severe liver damage, pancreatitis, and bone marrow suppression.
Side effects of sodium valproate are often dose-dependent, meaning they are more likely to occur at higher doses. Many side effects, particularly gastrointestinal symptoms and tremor, may improve with time or with dose adjustment. The enteric-coated and prolonged-release formulations may cause fewer stomach-related side effects than immediate-release preparations. Always discuss any persistent or troubling side effects with your doctor, as dosage modifications or formulation changes may help.
Very Common
May affect more than 1 in 10 people
- Tremor (shaking hands)
- Nausea
Common
May affect up to 1 in 10 people
- Stomach pain, vomiting, diarrhea
- Gum problems, oral mucosa inflammation
- Temporary or dose-dependent hair loss
- Nail and nail bed problems
- Allergic skin reactions
- Increased appetite, abnormal weight gain, loss of appetite, weight loss
- Confusion, hallucinations, aggression, agitation, attention problems
- Dizziness, drowsiness, seizures, memory impairment, headache
- Rapid involuntary eye movements (nystagmus)
- Increased bleeding tendency (reduced platelet count)
- Anemia
- Painful menstruation, hearing loss
- Liver function changes
- Decreased sodium levels in the blood
- Urinary incontinence
Uncommon
May affect up to 1 in 100 people
- Tingling or numbness (paresthesia), coordination problems
- Transient parkinsonism (tremor, stiffness), unsteady gait
- Reduced consciousness, coma, brain involvement
- Worsened seizures
- Insomnia
- Reduced white blood cell count (leukopenia)
- Increased urination frequency, impaired kidney function
- Swelling (edema), fluid retention
- Low body temperature (hypothermia)
- Fatigue
- Hair changes (color, texture, growth)
- Irregular or absent menstruation, elevated male hormone levels
- Pancreatitis (inflammation of the pancreas)
- Vasculitis (blood vessel inflammation)
- Pleural effusion (fluid around the lungs)
- Angioedema (swelling of face, tongue, or throat)
- Bone density reduction, osteoporosis, fractures
Rare
May affect up to 1 in 1,000 people
- Severe liver damage (hepatotoxicity, potentially fatal)
- Agranulocytosis (severe reduction in white blood cells)
- Rhabdomyolysis (severe muscle breakdown)
- Stevens-Johnson syndrome, toxic epidermal necrolysis (severe skin reactions)
- Hyperammonemic encephalopathy (elevated brain ammonia levels)
- Systemic lupus erythematosus (autoimmune disease)
- Psychosis, behavioral abnormalities, learning difficulties
- Bone marrow suppression (pancytopenia)
- Male infertility (usually reversible)
- Polycystic ovaries
- Biotin deficiency
- Fanconi syndrome (kidney tubular disorder)
- Hypothyroidism (underactive thyroid)
- DRESS syndrome (drug reaction with eosinophilia and systemic symptoms)
Some side effects of valproate are more frequent or more severe in children compared with adults. These include liver damage, pancreatitis, aggressive behavior, agitation, attention problems, abnormal behavior, hyperactivity, and learning difficulties. Close monitoring is essential throughout treatment in pediatric patients.
Driving and Operating Machinery
Absenor may impair reaction time and cognitive function. This should be considered when engaging in activities requiring alertness, such as driving or operating heavy machinery. You are personally responsible for assessing whether you are fit to drive or perform work that requires sharp attention. Drowsiness, dizziness, and visual disturbances are among the effects that may impair your ability. Discuss this with your doctor if you are uncertain.
How Should You Store Absenor?
Store Absenor in its original packaging, tightly closed, and protected from moisture. Keep out of the sight and reach of children. Do not use after the expiry date printed on the package.
Proper storage is important to maintain the effectiveness and safety of your medication. Sodium valproate is sensitive to moisture, so the following precautions should be observed:
- Store in the original packaging with the container tightly closed to protect from moisture
- Keep out of the sight and reach of children at all times
- Do not use after the expiry date stated on the packaging (the expiry date refers to the last day of that month)
- Absenor Depot packaging contains a desiccant capsule to absorb moisture – do not remove it
- Do not dispose of medications in household waste or wastewater. Return unused medicines to your pharmacy for safe disposal to protect the environment.
What Does Absenor Contain?
The active ingredient in all Absenor formulations is sodium valproate. The inactive ingredients differ between the enteric-coated and prolonged-release (Depot) formulations. Importantly, Absenor Depot contains soy lecithin and must not be used by people allergic to peanuts or soy. Both formulations contain sodium.
Active Ingredient
Sodium valproate (the sodium salt of valproic acid) is available in the following strengths:
- Enteric-coated tablets: 100 mg, 300 mg
- Prolonged-release tablets (Depot): 300 mg
Inactive Ingredients
Enteric-coated tablets: Povidone, calcium silicate, talc, magnesium stearate, partially hydrolyzed polyvinyl alcohol, titanium dioxide, macrogol, polyvinyl acetate phthalate, sodium hydrogen carbonate, triethyl citrate, stearic acid, sodium alginate, anhydrous colloidal silicon dioxide, simeticone.
Prolonged-release tablets (Depot): Copovidone, hypromellose, anhydrous colloidal silicon dioxide, magnesium stearate, polyvinyl alcohol, titanium dioxide (E171), talc, lecithin (soy) (E322), xanthan gum.
Sodium Content
Absenor contains sodium (the main component of table salt). This may be relevant if you are on a low-sodium diet. The sodium content per tablet is:
| Formulation | Sodium per Tablet | % of Recommended Daily Intake |
|---|---|---|
| Enteric-coated 100 mg | 14 mg | 0.7% |
| Enteric-coated 300 mg | 42 mg | 2.1% |
| Depot 300 mg | 42 mg | 2.1% |
If your daily dose of Absenor is 2,800 mg or more, and especially if you are on a low-sodium diet, consult your doctor or pharmacist about the sodium content.
Appearance
Enteric-coated tablets: White, round, convex tablets. The 100 mg tablets are 7.4 mm in diameter, 300 mg tablets are 10.4 mm.
Prolonged-release tablets (Depot): The 300 mg tablets are white, round, film-coated, convex, 12.5 mm in diameter. The Depot packaging includes a desiccant capsule.
Frequently Asked Questions About Absenor
Absenor (standard) comes as enteric-coated tablets with a protective coating that prevents dissolution until the intestine, reducing stomach irritation. Absenor Depot contains prolonged-release tablets that release the active ingredient slowly over time. The Depot formulation provides more stable blood levels throughout the day, which may improve seizure control and reduce side effects. The Depot version can often be taken once or twice daily instead of two to three times daily. Your doctor will decide which formulation is most suitable for you.
Absenor carries serious risks during pregnancy. For bipolar disorder, it must NOT be used during pregnancy at all. For epilepsy, it should only be used if no other treatment works. Approximately 11 out of 100 babies exposed to valproate in the womb are born with birth defects (compared to 2–3 per 100 in the general population), and up to 30–40% of exposed children may experience neurodevelopmental problems. All women of childbearing potential must use effective contraception throughout treatment. If you are planning a pregnancy or become pregnant, contact your doctor immediately – but do not stop taking Absenor without medical advice.
Stopping Absenor suddenly can be dangerous, particularly for epilepsy patients. Abrupt discontinuation may trigger breakthrough seizures, including potentially life-threatening status epilepticus (a prolonged seizure that does not stop on its own). For bipolar disorder, sudden discontinuation may cause rapid mood changes or manic episodes. Your doctor will always taper the dose gradually when it is time to stop or switch medications. Never change your dose or stop taking Absenor without consulting your doctor first.
Yes, this is completely normal with Absenor Depot (prolonged-release tablets). The tablet has a special matrix structure that releases the active ingredient slowly. After the medication has been released, the empty tablet shell passes through the digestive system and may be visible in your stool. This does not mean the medication is not working. The active ingredient has already been absorbed into your body before the shell is expelled.
Weight gain is a recognized side effect of Absenor and occurs commonly (affecting up to 1 in 10 people). The mechanism is not entirely clear but may involve increased appetite, metabolic changes, and effects on insulin sensitivity. Not everyone experiences weight gain, and the extent varies between individuals. If weight gain becomes a concern, discuss this with your doctor. They may recommend dietary changes, exercise, or in some cases, consider alternative medications. Weight is typically reversible when the medication is discontinued.
Regular blood monitoring is essential during Absenor treatment. Your doctor will typically check: liver function tests (ALT, AST, bilirubin), pancreatic enzymes (amylase, lipase), complete blood count with platelet count, and sometimes valproate blood levels to ensure they are within the therapeutic range. These tests are most frequent during the first 6 months of treatment (often monthly) and then at regular intervals thereafter (every 3–6 months). Additional blood tests will be performed before any surgical procedures. Always attend your scheduled blood test appointments.
References
- European Medicines Agency (EMA). Valproate and related substances – PRAC assessment report. EMA/198940/2018. Updated 2024.
- World Health Organization (WHO). WHO Model List of Essential Medicines – 23rd List, 2023. Valproic acid listed as an essential anticonvulsant.
- National Institute for Health and Care Excellence (NICE). Epilepsies in children, young people and adults. NICE guideline [NG217]. Updated 2024.
- Tomson T, Battino D, Perucca E. Valproic acid after five decades of use in epilepsy: time to reconsider the indications of a time-honoured drug. The Lancet Neurology. 2016;15(2):210-218.
- Bromley RL, et al. Treatment for epilepsy in pregnancy: neurodevelopmental outcomes in the child. Cochrane Database of Systematic Reviews. 2014;(10):CD010236.
- Cipriani A, et al. Valproic acid, valproate and divalproex in the acute treatment of bipolar mania: a systematic review and meta-analysis. Journal of Affective Disorders. 2023;327:245-253.
- Perucca E. Pharmacological and therapeutic properties of valproate: a summary after 35 years of clinical experience. CNS Drugs. 2002;16(10):695-714.
- FDA Drug Safety Communication. Valproate anti-seizure products – contraindicated for migraine prevention in pregnant women. Updated 2023.
- European Medicines Agency. New measures to avoid valproate exposure in pregnancy endorsed. EMA/375438/2018.
- Meador KJ, et al. Fetal antiepileptic drug exposure and cognitive outcomes at age 6 years (NEAD study): a prospective observational study. The Lancet Neurology. 2013;12(3):244-252.
About the Medical Editorial Team
This article was written and reviewed by the iMedic Medical Editorial Team, which includes specialists in neurology, clinical pharmacology, and psychiatry. All content follows international clinical guidelines and is based on evidence level 1A (systematic reviews and meta-analyses of randomized controlled trials).
All drug information is independently verified against official sources including EMA Summary of Product Characteristics (SmPC), FDA prescribing information, and WHO essential medicines guidelines. Content is updated whenever new safety information becomes available.
iMedic receives no funding from pharmaceutical companies. All content is editorially independent. Our editorial team has no financial relationships with any manufacturer of the medications described.