Medication: BenztropineShow answers too
Benztropine or benzatropine is commonly known by the brand name Cogentin®. It is one of a group of medicines called the anticholinergics or antimuscarinics, which are maily used to help control some of the common side-effects which can occur with some antipsychotic or neuroleptic drugs. These side effects include tremors or shaking, stiffness or movement problems and are known as the "Extra-pyramidal side effects" or "Parkinsonian" side effects. The anticholinergic drugs are very effective for this but as these side effects tend to wear off, you may not need to take an anticholinergic all the time.
Benztropine is available as tablets. It is available in Australia but was discontinued in UK in 2008. The nearest similar anticholinergic medicine is probably procyclidine.
- Where can I print information about benzatropine?
There are several options for printing:
- Click "Print this page" on the left to print the whole section
- Download a handy PILL (Patient Information Leaflet), a two-page summary of the main questions and answers from here for benzatropine. This can then be printed.
- Download a handy BILL (Brief Information Leaflet), a one-page larger print summary of the main questions and answers from here. This can then be printed.
There are many other Patient Information Leaflets (PILs) across the world for patients and carers. There are also official information leaflets (often called a Data Sheet, Package Insert, or Summary of Product Characteristics). They are not on our site, so we can't take any responsibility for them but you can click here for links to other sites and leaflets.
- WHAT IT IS:
- What are anticholinergics used for?
Anticholinergics (or antimuscarinics) are most often used to help control some of the common side-effects which can occur with some antipsychotics (neuroleptics or major tranquillisers) e.g. tremor or shaking, stiffness or movement problems. The side effects of e.g. tremor or shaking, stiffness or movement problems are known as the "Extra-pyramidal side effects" or "Parkinsonian" side effects. The anticholinergics are very effective for this but as these side effects tend to wear off, you may not need to take an anticholinergic all the time. The anticholinergics are also used to control the symptoms of Parkinson's Disease itself.
Antipsychotics are mainly used to help treat some of the symptoms of:
- What is the usual dose of benzatropine?
The usual dose of benzatropine in UK for side effects is 1-2mg once or twice a day. This can be either as a single dose or split up throughout the day. The usual top dose is 6mg a day. Older people get more side effects [Fox 2011] and so should have a lower dose.
It is not recommended for use in the under 18s, although it is not thought to be dangerous as such, just that there aren't any studies in younger people.
- What are the main alternatives to an anticholinergic?
There are not really many alternatives to the anticholinergics when used for the muscle stiffness or tremor side effects of antipsychotics. The main alternative would be, if possible, to reduce the antipsychotic dose or try another with less of that side effect. Sadly this is not always possible. There isn't much to choose between the anticholinergics available.
- How do anticholinergics work?
Many of the symptoms of "psychosis" are caused by an over-activity of dopamine in the brain. Dopamine is a naturally occurring chemical messenger ("neurotransmitter") in the brain. Antipsychotic drugs block the action of this dopamine in the brain. However, dopamine is also important in controlling muscle tone or tension. Unfortunately, the antipsychotic drugs also block these muscular actions of dopamine and the tremor, stiffness or movement problems mentioned above then occur due to this imbalance of dopamine in the brain. In people who get these side-effects, the effects of the transmitter 'acetylcholine' are greater than normal. Acetylcholine causes the muscles to become stiffer. Antimuscarinic or anticholinergic drugs block or reduce some of the action of acetylcholine in the brain and so reduces these side-effects. For a more detailed explanation, click here. Some antipsychotics (especially the phenothiazines) also block acetylcholine receptors, which is partly useful in minimising this problem. It is not, however, usually enough to counteract the effects of the antipsychotic on dopamine.
- STARTING, TAKING AND STOPPING:
- When should I take this anticholinergic?
Take your anticholinergic as directed on the medicine label. These medicines can give you a dry mouth. This can be helped by taking your medicine before food. They may also cause you to feel a bit sick or give you an upset stomach. If this happens it is best to take it after food as this will help. If you have a dry mouth, try taking your medicine after food and then sucking a peppermint, chewing gum or drinking water to help your thirst and stop your mouth getting dry.
Benztropine ("Cogentin") and Biperidin ("Akineton") can both cause you to feel sleepy so if the instructions say to take them once a day this is usually best at bedtime. They are not sleeping tablets. Benzhexol/trihexyphenidyl ("Artane"), orphenadrine ("Disipal") and procyclidine ("Kemadrin") can have the opposite effect. You should avoid taking these at night if possible as they may stop you getting off to sleep easily
- How should I take this anticholinergic?
The tablets should be swallowed with at least half a glass of water whilst sitting or standing. This is to make sure that they reach the stomach and do not stick in your throat.
Your pharmacist should give you a medicine spoon or oral syringe. Use it carefully to make sure you measure the correct amount. Ask your pharmacist for a medicine spoon if you do not have one.
- How long will this anticholinergic take to work?
The anticholinergics start to work with an hour or so and the effect lasts for about 8 to 12 hours.
- How long will I need to keep taking an anticholinergic for?
This should be discussed with your doctor as people respond differently. Once the doses of your other medicines have settled down you may not need to take them every day, only when you need them. If you are having a "depot" or long-acting injection you may only need these tablets for a few days after your injection.
- Are anticholinergics addictive?
For a drug to be addictive or produce dependence, then it must have a number of characteristics:
- should produce craving for the drug when the last dose "wears off"
- there should be a "reward" (e.g. a good feeling) from taking the drug
- should produce tolerance ie you need more drug to get the same effect
- should produce withdrawal symptoms specific to that drug.
These characteristics come from the World Health Organisation. Anticholinergics have none of these and so are not addictive. There have been some rare reports of people "abusing" them but this is uncommon, as they don't really have any stimulant or similar effects.
Click here to read a bit more about this, where you can find our thoughts on this knotty problem.
- What should I do if I forget to take a dose of this anticholinergic?
Start again as soon as you remember unless it is almost time for your next dose, then go on as before. Do not try to catch up by taking two or more doses at once as you may get more side-effects. You should tell your doctor about this next time you meet. If you forget some doses and do not notice any difference you may well not need to take them at the moment. Talk about this with your doctor.
If you have problems remembering your doses (as very many people do) ask you pharmacist, doctor or nurse about this. There are some special packs, boxes and devices that can be used to help you remember. You can try leaving the pack somewhere you will see it each morning e.g. in the bathroom, kitchen, by your bed etc.
- Can I stop taking an anticholinergic suddenly?
If you are taking them regularly it is best not to stop them suddenly as your side effects may then get worse. It is best to stop them gradually and you should discuss this with your doctor. If you are only taking them "when required" there is no problem.
- UNWANTED EFFECTS:
- What sort of side-effects might I get if I am taking this anticholinergic?
The table below will show you some of the main side effects you might get from an anticholinergic.
What to do about it
COMMON (less than about 1 in 10 people might get these)
Things look fuzzy and you can't focus properly.
Don't drive. See your doctor if you are worried.
Not enough saliva or spit.
Suck boiled sweets or wine gums (but be careful if you are putting on weight). If it is still bad, your doctor may be able to give you a mouth spray.
When you want to poop but can't (the opposite of diarrhoea). You can't pass a motion.
Make sure you eat enough fibre, cereal or fruit. Make sure you are drinking enough fluid. Make sure you keep active and get some exercise e.g. walking. If this does not help, ask your doctor or pharmacist for a mild laxative.
RARE (less than about 1 in 100 people might get these)
This includes feeling sick and getting diarrhoea (the runs).
If you feel like this for more than a week after starting an anticholinergic, tell your doctor. Taking it with food may help.
Not much urine passed.
Contact your doctor now.
Feeling light-headed and faint.
Your dose may be too high, contact your doctor. Don't stand up too quickly. Try and lie down when you feel it coming. Don't drive.
Your mind is all mixed up.
Your dose may be too high. Contact your doctor.
Do not be worried by this list of side effects. Some people get no side effects at all and others may get some effects that are not listed in this table. Side effects tend to be worse with higher doses. Starting with a lower dose sometimes helps. If you think you might have a side effect to your medicine, you should discuss this with your doctor, nurse of pharmacist. You should also see the manufacturer's information leaflet.
- Will taking this anticholinergic make me sleepy?
Trihexyphenidyl (benzhexol), orphenadrine and procyclidine can have an alerting effect, but can also slow down your reactions. You should not drive (see below) or operate machinery until you know how they affect you. You should avoid taking these at night if possible as they may stop you getting off to sleep easily.
- Will taking this anticholinergic cause me to put on weight?
It is not thought that any of the anticholinergics cause any changes in weight. If you do start to have problems with your weight, however, tell your doctor next time you meet as he or she can arrange for you to see a dietician for advice.
Click here for a few tips on how to help you feel less hungry and lose weight.
- Will this anticholinergic affect my sex life?
Drugs can affect desire (libido), arousal (erection) and orgasmic ability. The anticholinergics have not been reported to have a major effect on any of these three stages. However, if this does happen, you should discuss this with your doctor, as a change in dose may help minimise the problem.
- INTERACTIONS, FOOD AND DRINK:
Please see the separate medicines.
- Are there any foods or drinks that I should avoid if I am taking this anticholinergic?
You should have no problem with any foods or drinks, other than alcohol (see separate question). As far as we know there is no problem with drinking grapefruit juice with an anticholinergic.
- Can I drink alcohol while I am taking this anticholinergic?
Whether or not it is safe to drink alcohol with any medicine will depend on:
- How much you have to drink e.g. the amount and over how long
- What you then try to do (e.g. sleep or drive)
- If you have any other conditions e.g. asthma or a chest infection (as alcohol can make it harder to breathe), epilepsy
- If you are taking any other medicines
Alcohol reaches all parts of the brain and can affect many things e.g. thinking, reactions and breathing. Alcohol can also boost the effect of GABA (the brain's main calming chemical messenger).
If you are taking an anticholinergic, you should avoid alcohol as it may make you feel more sleepy. If this happens, you must take extra care if you need to drive or operate machinery. You must seek advice on this.
It is not safe to drive after drinking alcohol, with or without an anticholinergic. Some countries allow driving after a small amount of alcohol but others have a zero tolerance. The UK has the highest limit in Europe, France lower, Scandanavia even lower and zero in some Eastern European countries. It is not possible to say what blood level you might have from a drink so it is safest not to drink if you know you may have to drive. It is taken as a very serious offence in most countries. You should see National Guidelines, laws and regulations in the country in which you are driving.
- Will this anticholinergic affect my other medicines?
The anticholinergics have a few interactions with other medicines:
- The effects of anticholinergics can sometimes be increased by SSRIs (e.g. citalopram, fluoxetine, paroxetine, sertraline), some older antipsychotics, tricyclics (e.g. dosulepin/dothiepin, imipramine, lofepramine) or memantine (used for Alzheimer's Disease)
- Anticholinesterases used for Alzheimer's Disease (because anticholinergics decrease the effect of acetylcholine in the brain or anticholinesterases [e.g. donepezil, rivastigmine and galantamine] increase the effect of acetylcholine)
- Anticholinergics can sometimes slightly decrease the effect of cimetidine (for stomach problems)
This does not necessarily mean that this will happen in everyone or that some of these medicines can not be used together. It is just that you may need to follow your doctor's instructions very carefully. There are many other possible drug interactions.
- Are there any problems with smoking with this anticholinergic?
Cigarette smoke contains over 3000 different chemicals. Some of these chemicals can make some of the enzymes in the liver work faster (called "enzyme induction" of e.g. CYP1A2 or P4501A2). This means that any medicine those enzymes break down will be broken down quicker. So, you'll end up with less of that medicine if you smoke. And also you will have more of it in the body if you stop smoking. However, it seems that there are no extra problems if smoking with any of the anticholinergics.
- What about illicit drugs such as cannabis, cocaine, ecstasy and opiates with this anticholinergic?
By including this section, we're not saying it's right to take illicit or illegal drugs, because it isn't. We're just trying to answer the questions as best we can under the circumstances. With illicit drugs, the full answer is usually that we don't really know. So, we can only go on a few studies, a few reports and what we know about the drugs themselves.
Cannabis (illegal in most countries):
Smoking cannabis increases the amount of dopamine in the pleasure centres of the brain, which is where the reward or buzz comes from. However, psychosis also comes from having too much dopamine in another area of the brain. You have to remember that cannabis can increase dopamine in all areas of the brain and so can make psychosis worse. Please be careful, everything in moderation and if dope makes you worse, keep off the grass. It really won't help you in the long-term. Don't forget that if you're a toker, you're also a smoker, so see the question above. However, the anticholinergics do not seem to be affected so there seem to be no extra problems if smoking cannabis with an anticholinergic, although this might make you feel a bit more drowsy and may have more dry mouth, blurred vision and finding it hard to pass water (wee). Since you're probably also taking an antipsychotic, you must read that section too.
Cocaine (illegal in most countries)
Cocaine is of course highly addictive and has many adverse or side effects on the body and brain. It can make most mental health symptoms worse in the long-term. However, there are no reports of extra problems with the anticholinergics and cocaine, although this doesn't mean it's safe.
Ecstasy (illegal in most countries)
Ecstasy has many effects on the brain, the main ones producing the high seem to be by boosting serotonin, noradrenaline and dopamine in the brain. While it can cause a high, the effect wears off fairly quickly. It seems that the toxic effects on the brain are cumulative i.e. the more tablets you have over your lifetime, the more chance you have of having damage to the brain e.g. long-term depression and poor memory. However, there are no reports of extra problems with the anticholinergics and ecstasy, but again this doesn't mean it's safe.
The opiates include many chemicals, some of which are used in medical care (e.g. codeine for diarrhoea and stopping coughs, diamorphine and morphine for pain). However, there are no extra problems reported from taking opiates (e.g. heroin, methadone, codeine) with the anticholinergics. But again this doesn't mean it's safe.
- WOMEN'S HEALTH:
- If I am taking a contraceptive pill, will this be affected by taking this anticholinergic?
You should have no problems with "The Pill" and any of the anticholinergics.
- Will emergency contraception (the "morning-after pill") work if I am taking this anticholinergic?
In the UK, Levonelle one step® is available and is usually known as 'the morning after pill'. It is taken to reduce the chances of becoming pregnant after unprotected sex or failure of a contraceptive method. In fact "Emergency Contraception" is the better term because it can be taken up to 72 hours (3 days) afterwards. It can be bought over-the-counter without a prescription from pharmacies. EllaOne® tablets (which may work up to 5 days afterwards) and a coil (Intra-uterine device) can also be used but must be prescribed by a Doctor.
If you are taking an anticholinergic, the usual dose should work if you follow the instructions carefully.
N.B. We accept that for religious, cultural or ethical reasons some people do not approve of, or agree with, the use of the "Morning After" pill. However, we have answered the question because it is one of the most often asked of NHS Direct in UK, and they suggested we include it.
- Will this anticholinergic affect my periods (menstrual cycle)?
Several female functions such as menstrual cycle (e.g. your periods) are controlled by a hormone called prolactin. Prolactin in the body rises during and after pregnancy and this triggers the body to make breast milk. The amount of prolactin in the body is kept in control by one part of the brain uses dopamine as its chemical messenger. Some medicines (especially antipsychotics) block the effect of dopamine in the brain.
Luckily the anticholinergics do not seem to have any effect on dopamine in this part of the brain and so should not have any effect on your periods. If your periods are irregular or late, or you start leaking milk, then you should see your doctor about this to find the cause.
- What if I want to start a family or discover I'm pregnant while I am taking this anticholinergic?
It is important to consider that there will be a risk to you and your child from taking a medicine during pregnancy but also a possible risk from stopping the medicine e.g. getting ill again. Unfortunately, no decision is risk-free. It will be for you to decide which is the least risk. All we can do here is to help you understand some of the issues, so you can make an informed decision. For your information, major malformations occur "spontaneously" in about 2-4% of all pregnancies, even if no drugs are taken. The main problem with medicines is termed "teratogenicity" i.e. a medicine causing a malformation in the unborn child. A medicine causing teratogenicity is called a "teratogen". Since a baby has completed it's main development between days 17 and 60 of the pregnancy (the so-called "first trimester") these first 2-16 weeks are the main concern. After that, there may be other problems e.g. some medicines may cause slower growth. The infant may also be affected after birth e.g. withdrawal effects are possible with some drugs.
If possible, the best option is to plan in advance. If you think you could become pregnant, discuss this with your doctor and it may be possible to switch to medicines thought to carry least risk, and take other risk-reducing steps e.g. adjusting doses, taking vitamin supplements etc. If you have just discovered you are pregnant, don't panic, but seek advice from your GP within the next few days if possible. He or she may also want to refer you on to someone with more specialist knowledge of your medicine.
Very few medicines have been shown to be completely safe in pregnancy and so no manufacturer or advisor can ever say any medicine is safe. They will usually advise not to take a medicine during pregnancy, unless the benefit is much greater than the risk. In the UK, there is the NTIS (National Teratology Information Service) who offer individual risk assessments. However, their advice should always be used to help you and your doctor decide what is the risk to you and your baby. There is a risk from taking the medicine and a risk should you stop a medicine e.g. you might become ill again and need to go back on the medication again. The advice offered here is just that i.e. advice, but may give you some idea about the possible risks and what (at the time of writing) is known through the medical press.
It may be helpful to know that in the USA, the FDA (Food and Drug Administration) classifies medicines in pregnancy in five groups:
A = Studies show no risk, so harm to the unborn child appears only a remote possibility
B = Animal and human studies indicate a lack of risk but are not fully conclusive
C = Animal studies indicate a risk but there is no safety data in humans
D = a definite risk exists but the benefit may outweigh the risk in some people
X = the risk outweighs any possible benefit
The anticholinergics are all classified as "C". There is no firm evidence of a teratogenic effect, but some problems have been reported and so you should seek personal advice from your GP, who may then if necessary seek further specialist advice.
- Can I breast-feed if I am taking this anticholinergic?
Almost every medicine passes into breast-milk. The main questions are how much and if this is likely to have an effect on your baby. But also remember that being ill (e.g. depressed, manic, psychotic) may have more harmful and lasting effects on you and your child (such as bonding and behaviour e.g. Field, 2010) than a small amount of an effective medicine. If you have been taking a medicine while you are pregnant, you should usually be able to carry on as the amount in breast-milk is much less than the baby would have got while you were pregnant. It is usually thought to be fairly safe if the baby gets less than 10% of the mum's dose. But there may be times when although a medicine gets into breast milk the benefit may be worth the risk, so you should seek personal advice on this.
If you stop any medicine suddenly, some people can get discontinuation or withdrawal symptoms (see question above). If you have been taking a medicine during pregnancy, the same can sometimes happen to the baby when born. If the drug gets into breast milk, this can reduce the effect of suddenly not having the medicine (as well as coping with being in the big wide world too).
If you want to breast-feed there are some things you can do to reduce any risk:
- Nearly all medicines can be taken once a day. So, taking your daily dose just before the baby's longest sleep (often this will be at night) will reduce the amount the baby gets from the milk.
- Any side effects in the baby will be higher if the mum is taking a higher dose. So, try to take the lowest dose possible to still get an effect.
- Try not to take any medicines you don't really need. This includes any medicines you might buy over-the-counter
- Make sure your nurse, health visitor or doctor checks your baby for any side effects e.g. being extra sleepy, having colic, feeding problems, being floppy or poor weight gain. If there are any problems you might need to switch medicines or drop your dose a bit
- Hind milk (the second half of the feed) is likely to contain slightly more of any medicine than the first half
- Avoid new medicines if possible as there is less information about them and breast-feeding.
You must be extra careful of any medicines if your baby was pre-mature, or has kidney, liver, heart or brain problems.
We don't really know about anticholinergics. It is officially not recommended and the risk would seem to be there so we wouldn't recommend it either.
- OTHER QUESTIONS AND ANSWERS:
- Can I drive while I am taking an anticholinergic?
The anticholinergics can affect your driving in two ways. Firstly, you may feel drowsy and/or suffer from blurred vision at first when taking any of these drugs. Secondly, anticholinergics can slow down your reactions or reflexes. This is especially true if you also have a dry mouth, blurred vision, constipation etc. (the so-called "anticholinergic side effects"). Until these wear off, or you know how your anticholinergic affects you, do not drive or operate machinery. You should be careful as they may affect your reaction times or reflexes even though you feel well.
If you are taking any medicines, the rules about driving will depend on the country you’re driving in. Click on the links below for advice:
Medicines and driving in the UK (England, Scotland, Northern Ireland and Wales)
General advice on driving safely
If you want to drive, you should take sensible steps to reduce any risk. These could include:
- Avoid driving when you are tired or ill
- Do not drive after having any alcohol as this can make any drowsiness worse (a third of all fatal road traffic incidents involve alcohol-dependent drivers)
- Avoid driving at night, dusk or in bad weather
- Avoid motorways, dual carriageways and the rush hour
- Give yourself plenty of time. Don’t rush
- Be extra careful if you have not slept well the previous night
As some medicines can affect your driving, be extra careful:
- If starting a new medicine
- After a change in dose (especially an increase)
- If you are on a high dose or seem very sensitive to side effects
- If you are taking any medicines for other symptoms e.g. antihistamines for hay fever or allergies
- If your medicine causes you blurred vision, drowsiness, poor co-ordination, poor attention
If you are driving less than 2000 miles a year, once you consider insurance, tax, MoT, repairs, maintenance, parking and petrol, you may actually find it is cheaper to get taxis and busses, and walk the short journeys.
- Will I need any blood or other tests if I am taking this anticholinergic?
You should not need any blood or other tests to check on your anticholinergic.
- Where can I find more information about anticholinergics?
In 2012 the UK Medicines and Healthcare products Regulatory Agency set up a Medicines Safety Information part of their website. You will have to search for the medicine or medicines you want to look for, although there isn't much about the anticholinergics as they've been around a long time. The parts you might find of interest are as follows:
DAPs contain a complete list of all possible side effects that have been reported by healthcare professionals and patients to the MHRA, via the Yellow Card Scheme. Each DAP lists all of the reactions reported by health professionals and patients for a particular medicine.
- C&M note: Please be careful reading this section. It includes all possible side effects listed against every medicine someone was taking. So, if all your hair fell out while you were taking 5 medicines, this event would be listed against all five medicines, even though only one or even none might have been the cause. The idea is to try to get all information and perhaps find some rare side effects. The numbers of reported cases also depend on how often the medicine is prescribed e.g. 50 reports based on 500 prescriptions is worth looking at, but 5 cases based on 5,000,000 prescriptions could well just be chance.
The MHRA's assessment of a medicine can be found in the Public Assessment Reports (PARs), although commercial and personal confidential information has been taken out. PARs are usually available for medicines licensed in the UK after 30 October 2005.
A Risk Management Plan (RMP) is a document that describes all the available knowledge about the safety and effectiveness of a medicine.
Drug Safety Update is the MHRAs monthly newsletter for healthcare professionals. It has information and clinical advice on the safe use of medicines.
This page contains the official product information. Every medicine pack includes a patient information leaflet (PIL), which provides information on using the medicine safely. PILs are based on the Summaries of Product Characteristics - a description of a medicinal product's properties and the conditions for its use. These are also linked from the leaflets question above.
The European Medicines Agency (EMA) is the body that approves medicines for use in the EU. The EPAR is all the scientific stuff put in a readable way. It explains how and why the Committee for Medicinal Products for Human Use (CHMP) looked at the information on each drug and decided to allow it to be marketed ("granting a marketing authorisation" as the call it).