What is benztropine mesylate-injection, and how does it work (mechanism of action)?

Benztropine is an oral and injectable synthetic
medication. It is structurally similar to atropine (AtroPen) and diphenhydramine
(Benadryl). Benztropine has anticholinergic effects. Anticholinergic drugs block
the action of acetylcholine, a neurotransmitter (chemical) that nerves use to
communicate with other nerves.

In Parkinson’s there is an imbalance between levels of dopamine and
acetylcholine neurotransmitters. Benztropine helps restore balance by blocking
the action of acetylcholine in the central nervous system (brain and spinal
cord). Benztropine may also block the uptake and storage of dopamine in the
central nervous system (CNS),
resulting in the prolongation of the effects of dopamine. Benztropine was
approved by the U.S. Food and Administration (FDA) in 1954.

What brand names are available for benztropine mesylate-injection?


Is benztropine mesylate-injection available as a generic drug?


Do I need a prescription for benztropine mesylate-injection?


What are the side effects of benztropine mesylate-injection?

Side effects associated with benztropine treatment include

  • rapid heartbeat,
  • confusion,
  • depression,
  • heat stroke,
  • tiredness,
  • memory problems,
  • nervousness,
  • numbness of fingers,
  • psychotic symptoms,
  • skin rash,
  • constipation,
  • nausea,
  • vomiting,
  • dry mouth,
  • urinary retention, and
  • blurred vision.

Which drugs or supplements interact with benztropine mesylate-injection?

: Co-adminstration of benztropine with other
anticholinergic agents increases the risk of anticholinergic side effects such

Commonly used drugs with moderate to significant anticholinergic effects are:

  • amantadine (Symmetral),
  • amoxapine,
    bupropion (Wellbutrin),
  • clozapine (Clozaril),
  • cyclobenzaprine (Flexeril),
  • disopyramide (Norpace),
  • maprotiline (Ludiomil),
  • olanzapine (Zyprexa),
  • orphenadrine (Norflex),
  • first generation antihistamines
    (for example, diphenhydramine),
  • phenothiazine, and
  • tricyclic

Benztropine blocks the activity of acetylcholine and can cancel or interfere
with the action of drugs that increase gastrointestinal motility (movement of
food through the GI tract). Example of such drugs includes:

Umeclidinium (Incruse Ellipta) and tiotropium (Spiriva) may increase the
anticholinergic side effects of benztropine. Coadminstration of these agents
with benztropine is not recommended.

Benztropine may increase the blood levels of thiazide diuretics. Caution
should be used when these agents are used together.

Benztropine may increase the risk of stomach ulcers from using potassium
chloride (Klor-Con). Combination treatment with both agents is generally not

Medically Reviewed by a Doctor on 5/10/2017

FDA Logo

Report Problems to the Food and Drug Administration

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.