Phenobarbital brands and prices in Pakistan

About Phenobarbital

Phenobarbital is an antiseizure (antiepileptic) medicine from the barbiturate group. It slows down activity in the brain, which helps prevent seizures (fits), and it also makes people sleepy (sedative). It is a prescription medicine. It comes as tablets and a liquid (elixir), and as an injection given by a doctor or nurse. It is one of the older epilepsy medicines, and WHO lists it as an essential medicine for epilepsy in adults and children. It can be habit-forming, so it must be taken only as prescribed.

Who should not take it, or should take care

• Do not take it if you are allergic to phenobarbital or any other barbiturate, or to any ingredient.
• Do not take it if you have acute intermittent porphyria (a rare blood disorder), severe breathing problems, or severe liver or kidney disease.
• The liquid should not be given to children who are hyperactive.
• Tell your doctor if you have ever had depression or thoughts of harming yourself, if you have lung problems, long-term pain, adrenal gland problems, or milder liver or kidney problems.
• Tell your doctor if you have ever misused alcohol, street drugs or prescription medicines, because phenobarbital can cause dependence.
• Older people are more likely to have confusion and memory problems. US advice is that older adults should usually avoid it.
• Pregnancy: phenobarbital raises the chance of birth defects such as heart defects and cleft lip or palate, and may affect the baby's growth, learning and thinking. It can also cause bleeding problems and sleepiness in the newborn. It is avoided in pregnancy unless it is really needed. If you are pregnant or planning a baby, talk to your doctor straight away, but do not stop taking it on your own, because seizures can harm both mother and baby. Folic acid is advised before and during pregnancy.
• Contraception: women who could become pregnant should use effective contraception while taking it and for a time after stopping, as their doctor advises. Phenobarbital can make hormonal contraception (pills, patches, rings, injections, implants and the emergency pill) work less well, so ask your doctor which method to use.
• Breastfeeding: it passes into breast milk and can make the baby sleepy, so breastfeeding is not usually advised. Ask your doctor.
• The liquid contains alcohol and benzyl alcohol. Tell your doctor if you have alcohol problems or liver disease, and before giving it to very young children.
• The tablets contain lactose, which matters for people with some rare sugar intolerances.
• Talk to your doctor before having a flu vaccine.

Medicines and drinks that can interact

• St John's wort (a herbal remedy): do not take it with phenobarbital. Talk to your doctor before stopping it if you already take it.
• Hormonal contraceptives, which may stop working properly
• Warfarin and similar blood thinners
• Other epilepsy medicines, such as phenytoin, sodium valproate, carbamazepine, lamotrigine and clonazepam
• Steroid medicines such as prednisolone or hydrocortisone, and ciclosporin
• Thyroid medicines such as levothyroxine; your doctor may check your thyroid when phenobarbital is started or stopped
• Antidepressants and antipsychotic medicines, which can make seizures harder to control
• Some antibiotics and antifungals, such as doxycycline, metronidazole, rifampicin, itraconazole and voriconazole
• Some HIV medicines and some cancer medicines
• Heart and blood pressure medicines, such as digitoxin, propranolol, nifedipine, diltiazem and verapamil
• Theophylline and montelukast (asthma medicines), and methadone
• Folic acid and vitamin D: the doses of these or of phenobarbital may need changing
• Alcohol and other medicines that cause sleepiness, which add to its sedating effect
• Always check with a doctor or pharmacist before starting any new medicine, herbal remedy or supplement

Always tell your doctor and pharmacist about every medicine, supplement and herbal product you take.

Using it safely

• Take it exactly as your doctor tells you. Your doctor may change the dose over time. Never take more, more often, or for longer than prescribed.
• If you forget a dose, take it when you remember unless the next one is nearly due. Never take two doses together.
• Do not stop taking it suddenly. This can cause withdrawal symptoms such as anxiety, shaking, sleep problems and dizziness, and can bring back seizures. If it needs to stop, your doctor will lower the dose slowly.
• For the liquid, ask your pharmacist how to measure each dose accurately, so that you give the right amount.
• Do not drink alcohol while taking it.
• It can make you drowsy. Do not drive or use machines until you know how it affects you.
• Tell any doctor, surgeon or dentist treating you that you take phenobarbital.
• Keep it in its original container, away from heat and damp, and out of the sight and reach of children, ideally locked away. Keep the liquid away from light.
• Never share it. Return unused medicine to a pharmacy and do not throw it in household waste or down the drain.

Common questions

Is phenobarbital addictive?
It can be habit-forming, especially with long use. Take it only as prescribed. Do not stop suddenly, as this can cause withdrawal and seizures. Talk to your doctor if you are worried.

Can I drink alcohol while taking phenobarbital?
No. Alcohol adds to the drowsiness and slowed breathing that phenobarbital can cause. The liquid form already contains alcohol.

Will phenobarbital affect my birth control?
Yes. It can make hormonal methods such as the pill, patch, ring, injection, implant and the emergency pill work less well. Ask your doctor about a reliable method while you take it.

Can I take phenobarbital in pregnancy?
It raises the risk of birth defects and other problems for the baby, so it is avoided unless it is really needed. If you are pregnant or planning a baby, see your doctor soon, but do not stop it on your own, because uncontrolled seizures are also dangerous.

What happens if someone takes too much?
Too much can cause deep sleepiness, confusion, slurred speech, unsteadiness, low body temperature and slow or stopped breathing. Call an ambulance straight away, and take the medicine pack with you if you can.

Prepared from the sources listed by the MedInfoBase team. General information, not medical advice: it gives no doses. Your doctor or pharmacist decides the medicine and dose for you.