Medications
Medications Commonly Used To Control Side Effects
Introduction
Another category of medications used in the treatment of schizophrenia are those used to treat the side effects of other medications. These drugs may be added to a patient’s list of medications to counteract some side effects, but we must remember, they have their own side effects.
Anticholinergics
Most are referred to as antiparkinsonian drugs because they have all been used to treat Parkinson’s Disease and are used to treat EPSE (extrapyramidal side effects). Diphenhydramine (Benadryl) is an exception. It is an antihistamine drug, but has some anticholinergic effects. These older antiparkinsonian drugs are also anticholinergic drugs and have their own anticholinergic side effects.
Mechanism
These medications block the effects of the neurotransmitter acetylchloline. This may become necessary because antipsychotic drugs block the neurotransmitter dopamine, which may result in a significant imbalance between the levels of dopamine and acetylcholine. The result is too much acetylcholine and all of its effects (see “Anticholinergic Side Effects”). To solve this problem, we give patients other drugs that block acetylcholine in an attempt to resolve this imbalance. They are known as drugs with anticholinergic properties.
Types
Antiparkinsonian medications include (with the exception of diphenhydramine):
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benztropine mesylate (Cogentin) -
diphenhydramine (Benadryl)
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trihexyphenidyl (Artane)
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procyclidine (Kemadrin)
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amantadine (Symmetrel).
Because they block acetylcholine, they have side effects of their own (anticholinergic) side effects.
Some medications used to treat schizophrenia have their own acetylcholine blocking properties and so these side effect medications may not be necessary in these instances. Some antipsychotic medications are also less likely to cause these side effects in the first place and side effect medications may not be necessary.
Let’s review this in simple terms.
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Parkinson’s Disease involves too little dopamine, which results in problems starting and continuing movement and tremors).
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Schizophrenia drugs block dopamine, resulting in a reduction in levels of dopamine. They may also produce excessive amounts of and too acetylcholine which may lead to parkinsonism.
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We use other (acetylcholine blocking, or anticholinergic) drugs which may cause their own side effects (antichilinergic side effects, a consequence of too little acetylcholine effects).
Other Drugs
There are also a few other drugs that may be used to counteract side effects of antipsychotic drugs.
Propranolol
A notable example is propranolol (Inderal), which can be particularly helpful in reducing akathisia.
Of course, as is the case with any medication, propranolol has its own potential side effects. It may slow heart rate, reduce blood pressure, and make it more difficult for patients with diabetes to be aware of insulin reactions. Fortunately, the doses that are usually sufficient to control akathisia generally do not produce serious changes in blood pressure or pulse. Diabetics should be vigilant for the signs of more difficulty managing their blood sugars. It is best to consult their medical doctor before taking this medication.
Quercetin
Quercetin is a member of a group of chemical known as bioflavinoids (plant pigments). It is a powerful antioxidant and is found naturally in red onions and apples, but can be purchased as a dietary supplement.
Pretreatment with this substance has been found to reduce vacuous chewing movements in rats.1 Vacuous chewing movements (rats chew when their mouth is empty) is an accepted model for Tardive Dyskinesia. This suggests that quercetin may be helpful to reduce symptoms of Tardive Dyskinesia or perhaps prevents its occurrence.
1Paltipatis S, Naidu, Amanpreet Singh, Psychopharmacology Vol 167, Number 4, June, 2003
(Sources: The author’s knowledge base, unless otherwise noted.)
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