Broflex (Trihexyphenidyl)

How does it work?

Broflex syrup contains the active ingredient trihexyphenidyl hydrochloride (previously known as benzhexol hydrochloride in the UK). (NB. Trihexyphenidyl is also available without a brand name, ie as the generic medicine.) Trihexyphenidyl is a type of medicine called an anticholinergic. Anticholinergic medicines (sometimes also called antimuscarinics) work by preventing the activity of a neurotransmitter called acetylcholine.

Neurotransmitters are chemical compounds that are found in the brain and nerves, and act as chemical messengers between the nerve cells. There are various different neurotransmitters in the body, with various different functions. Several diseases and conditions involve either overactivity or underactivity of certain neurotransmitters.

In Parkinson’s disease there is a deficiency in the brain of a neurotransmitter called dopamine. Normally in the brain there is a balance between the activity of dopamine and the activity of acetylcholine. However, in Parkinson's disease, the deficiency of dopamine causes overactivity of acetylcholine. This causes some of the symptoms of the disease.

Trihexyphenidyl works by blocking the receptors that acetylcholine acts on. This reduces the activity of the acetylcholine, and helps restore the balance of acetylcholine and dopamine in the brain. In this way, trihexyphenidyl helps control some of the symptoms of Parkinson's disease. It is most effective at reducing the tremor and rigidity associated with the disease, but it has little effect on the slow movements (bradykinesia).

By contrast, some mental illnesses, for example schizophrenia, are associated with overactivity of dopamine in the brain. Antipsychotic medicines that are used to treat these diseases work by decreasing the activity of dopamine in the brain. However, because they decrease dopamine they can produce side effects that resemble the symptoms of Parkinson's disease. These side effects are known as extrapyramidal side effects, and include abnormal face and body movements, restlessness and tremor. Trihexyphenidyl can therefore also be used to reduce this type of side effect.

What is it used for?

  • Parkinson's disease.
  • Abnormal movements of the hands, legs, face, neck and tongue (extrapyramidal symptoms) which are side effects of another medicine.

Warning!

  • This medicine may cause blurred vision or a reduction in alertness. If affected, you should take care when performing potentially hazardous tasks such as driving or operating machinary.
  • This medicine should not be stopped suddenly after long-term use, as this could cause your symptoms to come back. If this medicine is to be stopped it should be withdrawn gradually, following the instructions given by your doctor or pharmacist.

Use with caution in

  • Elderly people.
  • Decreased kidney function.
  • Decreased liver function.
  • Decreased heart function.
  • High blood pressure (hypertension).
  • Glaucoma.
  • Enlarged prostate gland (prostatic hypertrophy).
  • People with a blockage in (obstruction) in the genitourinary tract, eg in the kidneys, bladder, ureters or urethra.
  • People with a blockage (obstruction) in the stomach or intestines.
  • Abnormal muscle weakness (myaesthenia gravis).

Not to be used in

  • Rare hereditary problems of fructose intolerance, glucose-galactose malabsoprtion or sucrase-maltase insufficiency.
  • This medicine is not recommended for use in children.
  • This medicine is not recommended for use in people with a condition called tardive dyskinesia. This condition is a potential side effect of antipsychotic medicines and involves rhythmical involuntary movements of the tongue, face, mouth and jaw, sometimes accompanied by involuntary movements of the arms and legs.

This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy.If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

  • The safety of this medicine for use during pregnancy has not been established. It should not be used during pregnancy unless considered essential by your doctor. Seek medical advice from your doctor.
  • It is not known if this medicine passes into breast milk. The manufacturer states that it should not be used by women who are breastfeeding. Seek medical advice from your doctor.

Side effects

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.

  • Dry mouth.
  • Constipation.
  • Blurred vision.
  • Difficulty in sleeping (insomnia).
  • Confusion.
  • Agitation.
  • Restlessness.
  • False perceptions of things that are not really there (hallucinations).
  • A state of well-being, optimism and cheerfulness (euphoria).
  • Memory problems.

The side effects listed above may not include all of the side effects reported by the drug's manufacturer.For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

How can this medicine affect other medicines?

It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to ensure that the combination is safe.

Many groups of medicines have anticholinergic effects. If this medicine is taken in combination with any of these, there there is an increased likelihood of anticholinergic side effects, such as blurred vision, dry mouth, constipation and difficulty passing urine. Other medicines with anticholinergic effects include the following:

  • amantadine
  • antihistamines, eg brompheniramine, chlorphenamine
  • antispasmodics, eg hyoscine
  • antipsychotics, eg chlorpromazine, clozapine
  • certain antisickness medicines, eg promethazine, prochlorperazine, meclozine, cyclizine
  • certain medicines for abnormal heartbeats (antiarrhythmics), eg disopyramide, propafenone
  • MAOI antidepressants, eg phenelzine
  • medicines for urinary incontinence, eg oxybutynin, flavoxate, tolterodine, propiverine, trospium
  • memantine
  • muscle relaxants, eg baclofen
  • nefopam
  • other anticholinergics, eg procyclidine, orphenadrine
  • tricyclic or related antidepressants, eg amitriptyline, maprotiline.

If you experience a dry mouth as a side effect of this medicine you may find that medicines that are designed to dissolve and be absorbed from under the tongue, eg sublingual glyceryl trinitrate (GTN) tablets, become less effective. This is because the tablets do not dissolve properly in a dry mouth. To resolve this, drink a mouthful of water before taking sublingual tablets.

This medicine can reduce the motility of the gut and may therefore reduce the absorption of certain other medicines taken by mouth, for example levodopa (L-dopa) for Parkinson's disease and the antifungal medicine ketoconazole. If you are taking levodopa and start taking this medicine as well, let your doctor know if your levodopa seems to be less effective.

This medicine may reduce the effects of the following medicines on the gut:

  • cisapride
  • domperidone
  • metoclopramide.

This medicine has an opposite effect to cholinergic medicines, which work by increasing the activity of acetylcholine. If this medicine is used in combination with medicines that have cholinergic effects, the medicines may oppose each others effects, making one or both less effective. Medicines with cholinergic effects include the following:

  • medicines for myaesthenia gravis, eg neostigmine, edrophonium, distigmine, pyridostigmine
  • medicines for Alzheimer's disease, eg galantamine, donepezil, rivastigmine
  • tacrine.

Other medicines containing the same active ingredient

Trihexyphenidyl tablets are available without a brand name, ie as the generic medicine.