1. What’s phenytoin
Phenytoin is a medication used to deal with epilepsy. It may also be used to deal with trigeminal neuralgia, a kind of nerve ache that impacts your face.
Phenytoin is accessible on prescription. It comes as tablets that may be chewed or dissolved in water, capsules and a liquid that you simply swallow.
2. Key info
- It is regular to take phenytoin a few times a day. You possibly can take it with or with out meals.
- The most typical unwanted side effects of phenytoin are complications and feeling dizzy.
- It takes round 4 weeks for phenytoin to work.
- When you’ve got epilepsy, it is best to remain on the identical model of phenytoin, as different manufacturers might not work as effectively for you.
- For those who take it for trigeminal neuralgia, most individuals shouldn’t have to remain on the identical model.
3. Who can and can’t take phenytoin
Phenytoin will be taken by adults and kids of any age. Phenytoin will not be appropriate for some individuals.
To verify phenytoin is protected for you, inform your physician if you happen to:
- have ever had an allergic response to phenytoin or different medicines prior to now
- have liver or kidney issues
- have a blood dysfunction known as porphyria
- can’t have alcohol – phenytoin liquid incorporates a small quantity of alcohol
- have had a rash brought on by phenytoin prior to now
- are pregnant or planning to grow to be pregnant
- have ever had an allergic response to carmoisine (E122) or sundown yellow (E110) – some manufacturers of phenytoin liquid and tablets comprise these
- have an intolerance to or can’t take up some sugars – some manufacturers of phenytoin tablets comprise sugars
4. How and when to take phenytoin
Phenytoin is a prescription medication. It is vital to take it as suggested by your physician.
The standard dose of phenytoin to deal with epilepsy in:
- adults is between 200mg and 500mg a day, taken as 1 or 2 doses
- youngsters (aged 12 to 17 years) is between 300mg and 400mg, taken as 2 doses
- youngsters (aged as much as 11 years) varies relying on their weight
The standard dose to deal with trigeminal neuralgia in adults is between 300mg and 500mg a day, taken as 1 or 2 doses.
Find out how to take it
It is regular to take phenytoin a few times a day. You possibly can take it with or with out meals.
For those who take it twice a day, attempt to house your doses evenly by means of the day. For instance, very first thing within the morning and within the night.
- Capsules and tablets – swallow complete with a glass of water, milk or juice. Don’t chew them.
- Chewable tablets – will be swallowed complete with a glass of water or chewed.
- Liquid – this comes with a syringe or spoon that will help you measure it. For those who shouldn’t have a syringe or spoon, ask your pharmacist for one. Don’t use a kitchen teaspoon because it won’t provide the correct amount.
Will my dose go up or down?
To stop unwanted side effects, your physician will prescribe a low dose to begin with after which improve it over a number of weeks.
You would possibly have to have blood exams whenever you begin phenytoin or in case your dose is modified. That is to verify your dose is true. When you discover a dose that fits you, it’s going to often keep the identical.
How lengthy will I take it for?
- When you’ve got epilepsy, it is probably that after your situation is below management you may nonetheless have to take phenytoin for a few years.
- When you’ve got trigeminal neuralgia, phenytoin shall be continued for so long as crucial, generally a few years, except your ache will get higher or disappears altogether.
- Don’t cease taking phenytoin with out speaking to your physician first.
What if I neglect to take it?
For those who take phenytoin and miss a dose:
- as soon as a day – take the missed dose as quickly as you bear in mind. If it is lower than 12 hours earlier than the subsequent dose is due, it is higher to go away out the missed dose and take your subsequent dose as regular.
- twice a day – take the missed dose as quickly as you bear in mind. If it is lower than 8 hours earlier than the subsequent dose is due, it is higher to go away out the missed dose and take your subsequent dose as regular.
By no means take 2 doses on the identical time. By no means take an additional dose to make up for a forgotten one.
When you’ve got epilepsy, it is vital to take this medication frequently. Lacking doses might set off a match (seizure). For those who neglect doses usually, it could assist to set an alarm to remind you.
You may additionally ask your pharmacist for recommendation on different methods that will help you bear in mind to take your medication.
What if I take an excessive amount of?
Taking an excessive amount of phenytoin may cause disagreeable unwanted side effects.
Pressing recommendation: Name 111 for recommendation now if:
- you’re taking an excessive amount of phenytoin – even if you happen to shouldn’t have any unwanted side effects
If you could go to A&E, don’t drive your self. Get somebody to drive you or name for an ambulance.
Take the phenytoin packet or the leaflet inside it, plus any remaining medication, with you.
5. Negative effects
Like all medicines, phenytoin may cause unwanted side effects, though not everybody will get them.
Pores and skin rashes
It’s normal to get a pores and skin rash with phenytoin. Most pores and skin rashes aren’t critical.
However if you happen to develop a pores and skin rash or redness, inform a health care provider right away, as this may develop right into a life-threatening pores and skin situation known as Stevens-Johnson syndrome.
Stevens-Johnson syndrome is a uncommon facet impact of phenytoin.
It causes flu-like signs, adopted by a pink or purple rash that spreads and kinds blisters. The affected pores and skin finally dies and peels off.
It is extra more likely to occur within the first 8 weeks of beginning phenytoin, or when the dose is elevated too shortly.
It will probably additionally occur if phenytoin is stopped immediately for a couple of days after which restarted on the identical dose as earlier than, with out lowering the dose after which rising it slowly once more.
Stevens-Johnson syndrome is extra widespread in:
- individuals who have developed a rash earlier than with a unique epilepsy medication
- people who find themselves allergic to an antibiotic known as trimethoprim
- individuals additionally taking a medication known as sodium valproate
To assist stop the possibility of you getting a rash that might be confused with Stevens-Johnson syndrome, it is best to not begin any new medicines, meals or merchandise through the first 3 months of remedy with phenytoin.
It is also finest to not begin phenytoin inside 2 weeks of a viral an infection, vaccination or rash brought on by one thing else.
Widespread unwanted side effects
These widespread unwanted side effects might occur in additional than 1 in 100 individuals. They’re often gentle and go away by themselves.
Hold taking the medication and speak to your physician or pharmacist if these unwanted side effects hassle you or don’t go away:
- feeling drowsy, sleepy or dizzy
- feeling nervous, unsteady or shaky
- feeling or being sick (nausea or vomiting)
- sore or swollen gums
- gentle pores and skin rash
Some unwanted side effects of phenytoin put on off as soon as your physique will get used to the medication, however it could actually take a number of weeks or months.
Critical unwanted side effects
Only a few individuals taking phenytoin have critical issues.
Inform your physician right away when you’ve got a critical facet impact, together with:
- ideas of harming or killing your self – a small variety of individuals taking phenytoin have had suicidal ideas, which may occur after a couple of weeks of remedy
- surprising bruising or bleeding, a excessive temperature or sore throat – these might be warning indicators of a blood dysfunction
- a excessive temperature with swollen glands and a pores and skin rash, generally with yellowing of your pores and skin or the whites of your eyes, significantly within the first 2 months of remedy – these could also be indicators of a hypersensitivity response, which is extra more likely to occur if you happen to’re black African-Caribbean or have a weakened immune system
- a pores and skin rash – this is perhaps an indication of Stevens-Johnson syndrome
Critical allergic response
In uncommon circumstances, it is potential to have a critical allergic response (anaphylaxis) to phenytoin.
Speedy motion required:
- you get a pores and skin rash that will embrace itchy, pink, swollen, blistered or peeling pores and skin
- you are wheezing
- you get tightness within the chest or throat
- you might have hassle respiration or speaking
- your mouth, face, lips, tongue or throat begin swelling
You may be having a critical allergic response and might have speedy remedy in hospital.
These aren’t all of the unwanted side effects of phenytoin.
6. How to deal with unwanted side effects
What to do What’s:
- complications – ensure you relaxation and drink loads of fluids. Don’t drink an excessive amount of alcohol. If it is an issue, ask your pharmacist to suggest a painkiller. Speak to your physician in case your complications last more than per week or are extreme.
- feeling drowsy, sleepy or dizzy – as your physique will get used to phenytoin, these unwanted side effects ought to put on off. Don’t drive, trip a motorbike or function equipment till you are feeling extra alert. If they don’t go inside per week or two, your physician might scale back your dose or improve it extra slowly. If that doesn’t work, chances are you’ll want to change to a unique medication.
- feeling nervous, unsteady or shaky – speak to your physician if this bothers you. These signs could be a signal that the dose is simply too excessive for you.
- feeling or being sick – persist with easy meals and don’t eat wealthy or spicy meals. It’d assist to take your phenytoin after a meal or snack. For those who’re being sick, attempt taking small, frequent sips of water to keep away from dehydration. Indicators of dehydration embrace peeing lower than regular or having darkish, strong-smelling pee. Communicate to a health care provider in case your signs worsen or final greater than week.
- constipation – eat extra high-fibre meals, corresponding to recent fruit and greens, and cereals. Attempt to drink a number of glasses of water or one other non-alcoholic liquid every day. For those who can, attempt to train extra frequently – for instance, by occurring a each day stroll or run.
- sore or swollen gums – brush your enamel and gums twice a day to assist cease this taking place, and go to your dentist frequently
- gentle pores and skin rash – it could assist to take an antihistamine, which you should buy from a pharmacy. Examine with the pharmacist to see what kind is appropriate for you. Use lukewarm water fairly than sizzling within the bathe. Contact your physician if it spreads, will get very itchy or lasts greater than a few days.
7. Being pregnant and breastfeeding
Phenytoin and being pregnant
- Phenytoin has been linked to an elevated threat of issues in your unborn child.
- You may often solely be suggested to take it in case your physician thinks the advantages of the medication outweigh the dangers.
- It is vital that you simply and your child keep effectively throughout being pregnant.
- For those who take phenytoin and grow to be pregnant, inform your physician or nurse right away.
- When you’ve got epilepsy, it is essential that it is handled throughout being pregnant as seizures can hurt you and your unborn child.
- Don’t cease taking it with out speaking to your physician first.
- For those who’re pregnant or making an attempt to get pregnant and taking phenytoin, you are really helpful to take the next dose of folic acid, a vitamin that helps your child develop usually.
- Your physician would possibly prescribe a excessive dose of 5mg a day so that you can take whenever you’re making an attempt to get pregnant and through the first 12 weeks of being pregnant.
Phenytoin and breastfeeding
- In case your physician or well being customer says your child is wholesome, phenytoin will be taken when you’re breastfeeding.
- Phenytoin passes into breast milk in small quantities. There have been some experiences of unwanted side effects in breastfed infants, however typically infants don’t get any unwanted side effects.
- It is vital to maintain taking phenytoin to maintain you effectively. Don’t cease taking it with out speaking to your physician.
- Breastfeeding may even profit each you and your child.
- For those who discover that your child’s not feeding in addition to regular, appears unusually sleepy, or you might have another issues What’s them, speak to your pharmacist, well being customer or physician as quickly as potential.
Non-urgent recommendation: Inform your physician if you happen to’re:
- making an attempt to get pregnant
8. Cautions with different medicines
There are many medicines that may have an effect on phenytoin and improve the possibilities of you having unwanted side effects. If you could take these medicines, your physician might change your dose of phenytoin.
Inform your physician if you happen to’re taking:
- different medicines used to deal with epilepsy, corresponding to carbamazepine, clonazepam, lamotrigine, phenobarbital, sodium valproate, topiramate, oxcarbazepine, ethosuximide and vigabatrin
- medicines used to deal with HIV
- hormonal contraceptives or hormone alternative remedy (HRT)
- medicines used for coronary heart and circulation issues like digoxin, amiodarone, furosemide, warfarin, diltiazem, nifedipine, apixaban and ticagrelor
- medicines used to deal with fungal infections like fluconazole, itraconazole and miconazole
- medicines used for tuberculosis and different infections like isoniazid, rifampicin, sulfamethoxazole-trimethoprim, doxycycline and ciprofloxacin
- medicines used for abdomen issues like omeprazole, sucralfate, ranitidine and a few antacids
- theophylline, a medication to assist with respiration issues
- medicines used for sleeplessness and psychological well being issues like chlordiazepoxide, clozapine, clobazam, diazepam, disufiram, fluoxetine, quetiapine, trazodone and amitriptyline
- medicines used for transplants corresponding to ciclosporin and tacrolimus
- medicines used for most cancers
- bupropion, a medication that will help you quit smoking
This isn’t a full listing of medicines that may have an effect on phenytoin.
Mixing phenytoin with natural cures and dietary supplements
There could also be an issue taking some natural cures and dietary supplements alongside phenytoin. Don’t take St John’s wort with phenytoin, because it decreases the quantity of phenytoin in your blood.
For those who already take it, speak to your physician earlier than stopping St John’s wort as they could want to extend your phenytoin dose.
Inform your physician or pharmacist if you happen to’re taking another medicines, together with natural medicines, nutritional vitamins or dietary supplements.
9. Widespread questions What’s phenytoin
How does phenytoin work?
For epilepsy – mind cells usually “speak” to one another utilizing electrical alerts and chemical substances.
Seizures can occur when the mind cells aren't working correctly or working quicker than regular.
Phenytoin slows down these electrical alerts to cease seizures.
For nerve ache – phenytoin was not initially designed to deal with ache, however it could actually assist to alleviate nerve ache, corresponding to trigeminal neuralgia, by slowing down electrical impulses within the nerves and lowering their capacity to transmit ache.
How lengthy does it take to work?
-It often takes round 4 weeks for phenytoin to work correctly.
-It's because the dose of phenytoin must be elevated slowly to stop unwanted side effects.
-You should still have seizures or ache throughout this time.
Is it protected to take phenytoin for a very long time?
Many individuals can take phenytoin safely for a number of months or years. However there are some unwanted side effects that may occur over a very long time.
Lengthy-term remedy with phenytoin can:
-lower the quantity of vitamin D in your blood and would possibly result in osteoporosis and osteopenia, rising your threat of breaking a bone. If the quantity of vitamin D in your blood is low, your physician offers you vitamin D dietary supplements.
-trigger nerve injury (peripheral neuropathy), which may result in signs corresponding to numbness and tingling in palms or toes
-make the pores and skin in your face feel and appear coarse and grow to be barely bushy
-have an effect on your capacity to assume clearly, particularly in youngsters
Will I would like blood exams whereas taking phenytoin?
Your physician might measure the quantity of phenytoin in your blood:
-whenever you first begin taking it
-whenever you change your dose
-if you could change to a unique type of phenytoin (for instance, if you happen to change from tablets to the liquid)
The blood exams will assist your physician to resolve what dose is best for you and if they should improve or lower your dose.
Can I take phenytoin earlier than surgical procedure?
You possibly can take phenytoin as regular on the day of your surgical procedure, except your physician or surgeon has suggested you to not.
Will it have an effect on my contraception?
You should utilize the contraceptive injection or coil safely with phenytoin. Phenytoin would possibly cease these contraceptives working:
mixed hormonal contraceptives (the mixed capsule, patches and vaginal ring) – look out for bleeding between intervals, which is perhaps an indication the capsule will not be working. Speak to your physician if this occurs. Your physician might advise you to make use of a unique kind of contraceptive, or condoms in addition to mixed hormonal contraception.
progestogen-only contraceptive capsule and implants – your physician might advise you to make use of a unique kind of contraceptive that is not affected by phenytoin
emergency contraception – inform your physician or pharmacist that you simply take phenytoin if you happen to want emergency contraception. Chances are you'll want an elevated dose or to make use of the copper coil.
Will it have an effect on my fertility?
It isn't thought that phenytoin impacts feminine fertility. For some males with epilepsy, epilepsy medicines can scale back ranges of testosterone. It doesn't have an effect on everybody, however it might make you much less fertile. Communicate to your physician when you've got any issues.
Does phenytoin trigger weight reduction ?
Phenytoin doesn't often have an effect on weight in any respect.
Can I get epilepsy medicines free of charge?
When you've got epilepsy, you are entitled to free prescriptions for your entire medicines, not simply your epilepsy ones. To assert your free prescriptions, you may want a medical exemption certificates. The applying type for the medical exemption certificates is known as FP92A.
You will get this out of your physician's surgical procedure. You may have to fill within the type, and your physician will signal it and ship it off.
Can I drink alcohol with it?
Sure, you possibly can often drink alcohol with phenytoin. However it could make you are feeling sleepy or drained, and alcohol and hangovers can deliver on seizures in some individuals with epilepsy.
In the course of the first few days of taking phenytoin, it is best to cease consuming alcohol till you see how the medication impacts you. Speak to your physician What's how a lot alcohol you drink. They might do blood exams to test every part is OK.
For those who do drink, attempt to not have greater than the really helpful tips of as much as 14 items of alcohol per week. A regular glass of wine (175ml) is 2 items. A pint of lager or beer is often 2 to three items of alcohol.
Is there any meals or drink I have to keep away from?
No, you possibly can eat and drink usually whereas taking phenytoin.
Can I drive or trip a motorbike with it?
Chances are you'll really feel sleepy or dizzy whenever you first begin taking phenytoin or the dose is elevated. If this occurs to you, don't drive, trip a motorbike or function equipment till you are feeling extra alert.
Phenytoin can even have an effect on your imaginative and prescient. Don't drive or trip a motorbike in case your imaginative and prescient is affected. When you've got epilepsy, you are not allowed to drive till you might have had no seizures for 1 12 months.
For those who change your epilepsy medication, your physician will let you know whether or not you could cease driving and for the way lengthy. Driving guidelines if you happen to change or withdraw your medication, Epilepsy Motion Epilepsy and driving info, GOV.UK
Are there comparable medicines?
There are many different medicines that can be utilized for epilepsy and trigeminal neuralgia, however they work in numerous methods. They could have totally different unwanted side effects, or be taken kind of usually. When you've got epilepsy, the selection will rely upon the kind of seizures that you've got. Your physician will talk about the very best medication for you.
When you've got trigeminal neuralgia, different medicines that your physician would possibly use embrace carbamazepine and gabapentin.
Do I would like to remain on the identical model of phenytoin?
When you've got epilepsy, it is best to remain on the identical model of phenytoin, as different manufacturers of phenytoin might not work as effectively for you. For those who take phenytoin for trigeminal neuralgia, most individuals shouldn't have to remain on the identical model.
Speak to your physician or pharmacist if you happen to can't get a provide of your regular model of phenytoin.
How does phenytoin evaluate with different medicines for epilepsy?
There are lots of totally different medicines for treating epilepsy. It isn't potential to say that one works higher than the opposite. It varies from individual to individual, and is determined by the kind of seizures and the way usually you might have them.
Different epilepsy medicines embrace:
Earlier than prescribing a medication, your physician may even keep in mind your age and gender, the medicines you are already taking and another well being issues you might have. It is regular to attempt to deal with epilepsy utilizing a single medication.
If this medication will not be working effectively otherwise you're getting unwanted side effects, your physician will often attempt you on a unique one.
If a single medication will not be stopping your seizures, your physician might suggest taking 2 or extra epilepsy medicines on the identical time.
How does phenytoin evaluate with different medicines for trigeminal neuralgia?
An epilepsy medication known as carbamazepine is often the primary medication given to deal with trigeminal neuralgia. Phenytoin is perhaps used if carbamazepine doesn't work or causes too many unwanted side effects.
Another medicines could also be used to deal with trigeminal neuralgia. Your physician or specialist will discover the medication that works finest for you.
Can I change to a unique medication?
For those who're switching medicines, it is essential to do it precisely as your physician tells you to. If you wish to change, you may often begin taking the brand new one at a low dose and slowly construct up the dose when you're nonetheless taking phenytoin.
As soon as you take the right dose of the brand new medication, you need to be capable of slowly scale back your dose of phenytoin. It will probably take a number of weeks or months till you might have stopped taking phenytoin utterly.
How can I come off phenytoin?
For those who're taking phenytoin for epilepsy, stopping it immediately may cause seizures. Coming off phenytoin must be executed very slowly and would possibly take a couple of months.
For those who're taking phenytoin for trigeminal neuralgia and your ache goes away, your physician will slowly scale back your dose as little as potential, or might even cease it.
For those who get a critical facet impact, corresponding to a extreme pores and skin rash, your physician might let you know to cease taking phenytoin right away, even when you've got epilepsy.
Don’t cease taking phenytoin with out speaking to your physician first.
- Epilepsy and being pregnant
- Trigeminal neuralgia
- HealthUnlocked: phenytoin discussion board
- UK Epilepsy & Being pregnant Register