Cogentin (benztropine) Side Effects, Warnings, and Drug Interactions

Cogentin (benztropine) is an oral and injectable anticholinergic medication used to manage drug-induced extrapyramidal disorders (except tardive dyskinesia) and to treat Parkinson’s disease. 

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

Common side effects of Cogentin include:

• skin rash,
• nausea,
• vomiting,
• dry mouth,
• tiredness,
• memory problems, and
• nervousness.

Serious side effects of Cogentin include:

• rapid heartbeat,
• confusion,
• hallucinations,
• depression,
• heatstroke,
• numbness of fingers,
• psychotic symptoms,
• loss of appetite,
• severe constipation,
• urinary retention,
• severe skin rash,
• blurred vision, and
• dehydration (symptoms include feeling very thirsty or hot, inability to urinate, heavy sweating, and hot and dry skin).

Drug interactions of Cogentin include:

• other anticholinergics, which increases the risk of anticholinergic side effects. 

Cogentin blocks the activity of acetylcholine and can cancel or interfere with the action of drugs that increase gastrointestinal motility. 

Umeclidinium and tiotropium may increase the anticholinergic side effects of Cogentin when taken together. 

Cogentin may increase the blood levels of thiazide diuretics. Cogentin may increase the risk of stomach ulcers from using potassium chloride. 

Safe use of Cogentin in pregnancy has not been established. Using Cogentin during pregnancy could harm a fetus.

It is not known if Cogentin is excreted in breast milk. However, antimuscarinic agents have been reported to suppress lactation in animals and decrease prolactin levels in the blood of nursing mothers. Due to the lack of safety data, Cogentin should be used cautiously in females who are breastfeeding or avoided.

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.

The adverse reactions below, most of which are anticholinergic in nature, have been reported and within each category are listed in order of decreasing severity.

Cardiovascular: Tachycardia.

Digestive: Paralytic ileus, constipation, vomiting, nausea, dry mouth.

If dry mouth is so severe that there is difficulty in swallowing or speaking, or loss of appetite and weight, reduce dosage, or discontinue the drug temporarily.

Slight reduction in dosage may control nausea and still give sufficient relief of symptoms. Vomiting may be controlled by temporary discontinuation, followed by resumption at a lower dosage.

Nervous System

Toxic psychosis, including confusion, disorientation, memory impairment, visual hallucinations; exacerbation of pre-existing psychotic symptoms; nervousness; depression; listlessness; numbness of fingers.

Special Senses

Blurred vision, dilated pupils.

Urogenital

Urinary retention, dysuria.

Metabolic/Immune or Skin

Occasionally, an allergic reaction, e.g., skin rash, develops. If this cannot be controlled by dosage reduction, the medication should be discontinued.

Other

Heat stroke, hyperthermia, fever.

To report SUSPECTED ADVERSE REACTIONS, contact Lundbeck Inc. at 1-800-455-1141 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

Antipsychotic drugs such as phenothiazines or haloperidol; tricyclic antidepressants.