Cogentin (Benztropine) Uses for Bipolar Disorder

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Medications often used to treat bipolar disorder, such as typical and atypical antipsychotic drugs, calcium channel blockers, as well as anticonvulsant medications, may cause drug-induced parkinsonism, the medical term for symptoms that mimic Parkinson's disease. 

Drug-induced parkinsonism may cause: 

  • A decrease in facial expressions
  • Difficulty starting and controlling movement
  • Loss or weakness of movement (paralysis)
  • Soft voice
  • Stiffness of the trunk, arms, or legs
  • Tremor

What Is Cogentin?

Cogentin (benztropine) is an antiparkinsonian drug in a class of drugs called anticholinergics. These drugs work by blocking a naturally occurring substance called acetylcholine. Cogentin improves muscle control and decreases the stiffness and tremors, and is therefore typically used in the treatment of Parkinson's disease and to control movement side effects of certain drugs such as those sometimes used in people with bipolar disorder.

Cogentin comes in 0.5, 1, and 2 mg tablets to be taken orally, usually at bedtime, but it may be taken multiple times a day to treat tremors. Your doctor may start you on a small dose to see how you respond. 


Cogentin may interact with certain drugs, including antidepressants, sleeping pills, painkillers, antihistamines, anti-diarrheal medications, some antacids, and other medications.

It's important that you speak with your doctor about any potential interactions. 

Common Side Effects 

The following are common side effects of ​Cogentin. You should check with your doctor if they don't go away or worsen:

  • Blurred vision 
  • Constipation 
  • Decreased sweating
  • Difficult or painful urination (especially in older men)
  • Drowsiness
  • Dryness of mouth, nose, or throat
  • Increased sensitivity of eyes to light
  • Nausea or vomiting

Less Common Side Effects 

The following are less common side effects of Cogentin. 

  • Dizziness or lightheadedness when getting up from a lying down or sitting position
  • False sense of well-being (especially in the elderly or with high doses)
  • Headache
  • Loss of memory (especially in the elderly)
  • Muscle cramps
  • Nervousness
  • Numbness or weakness in hands or feet
  • Soreness of mouth and tongue
  • Stomach upset or pain
  • Unusual excitement (more common with large doses of trihexyphenidyl)

When to Contact Your Doctor

Always notify your doctor immediately if you experience these rare side effects of Cogentin:

  • Confusion (more common in the elderly or with high doses)
  • Eye pain
  • Skin rash

Withdrawal Symptoms

If you need to discontinue using Cogentin, it's important to not discontinue it suddenly but to work with your doctor to taper off your dose gradually, unless there is a medical reason your doctor wants you to stop immediately.

Discontinuing Cogentin can cause withdrawal effects, in either case, so be sure to let your doctor know immediately if you experience any of these symptoms:

  • Anxiety
  • Difficulty in speaking or swallowing
  • Dizziness or lightheadedness when getting up from a lying or sitting position
  • Fast heartbeat
  • Loss of balance control
  • Mask-like face
  • Muscle spasms, especially of the face, neck, and back
  • Restlessness or desire to keep moving
  • Shuffling walk
  • Stiffness of arms or legs
  • Trembling and shaking of hands and fingers
  • Trouble sleeping
  • Twisting movements of the body

Overdose Effects

If you or a loved one have potentially overdosed on Cogentin, call your local poison control center and/or 911 immediately. Symptoms of overdose include:

  • Clumsiness or unsteadiness
  • Severe drowsiness 
  • Severe dryness of mouth, nose, or throat
  • Fast heartbeat
  • Hallucinations (seeing, hearing, or feeling things that are not there)
  • Mood or mental changes
  • Seizures
  • Shortness of breath or troubled breathing
  • Trouble sleeping
  • Warmth, dryness, and flushing of the skin

Other benztropine side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.

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Article Sources

  • Benztropine (Oral Route). Mayo Clinic (2015).

  • Psychiatric Medications: Benztropine. Stanford Medicine (2016).