What to Know About Cogentin (Benztropine)

Cogentin (benztropine) is an anticholinergic drug used for the treatment of Parkinson's disease. It is also sometimes prescribed to people with bipolar disorder who've developed parkinsonism, a condition that involves movement-related issues, stiffness, and tremors similar to those experienced with Parkinson's.

If you've been prescribed this medication, it can be helpful to know more about it. This includes understanding Cogentin's side effects, warnings, contraindications, and potential drug interactions.

Uses for Cogentin

Parkinsonism in bipolar disorder is usually a side effect of antipsychotic medications. This is referred to as drug-induced parkinsonism. Although, it can also be a sign of Parkinson's disease or a co-occurring disease involving reduced blood flow to the brain (cerebrovascular disease).

Drug-induced parkinsonism may cause: 

• A decrease in facial expressions
• Difficulty starting and controlling movement
• Slowed movement
• Soft voice
• Stiffness of the trunk, arms, or legs
• Tremors

Anticholinergics such as Cogentin help rebalance irregular activity of acetylcholine neurotransmitters, which are crucial to brain and muscle function. This can improve muscle control while decreasing rigidity and tremors.

Before Taking Cogentin

Before prescribing Cogentin, your healthcare provider will evaluate your symptoms and any co-occurring medical conditions that may be affected by the use of this medication. They will also consider other medications that you are currently taking before deciding if Cogentin is the right choice for your needs. 

In addition to Cogentin, Artane (trihexyphenidyl) may also be prescribed to treat parkinsonism. Artane is available in tablet and liquid elixir forms. Be sure to tell your provider if you are currently taking other anticholinergic medications before taking this drug.

Dosage of Cogentin

Cogentin used to come in tablet form, but this formulation of the drug has been discontinued—although not for reasons related to its safety or effectiveness. It is still available as an injection, with other generic benztropine options that may also exist.

When first starting Cogentin, a low dose is recommended. This dose can then be gradually increased by 0.5 mg every five or six days until optimal relief or a 6 mg maximum dose is achieved, with the usual daily dose being 1 mg to 2 mg, administered once or twice daily.

If you miss a dose of Cogentin, take it when you remember. If it's close to the time for your next dose, don't take the missed dose. Instead, take the next dose at the regular time, then resume your normal schedule.

Overdose

It is possible to overdose on benztropine. Symptoms of overdose range from feelings of excitement to coma, and can include:

• Blurry vision
• Confusion
• Dizziness
• Dry mouth
• Hallucinations
• Muscle weakness
• Nervousness
• Painful urination
• Rapid heartbeat
• Seizure
• Trouble swallowing
• Upset stomach or vomiting

How to Take and Store

Cogentin is typically delivered via injection into the muscle. In emergency situations, it can also be administered intravenously or in IV form so it is faster-acting. Storing it at room temperature, or between 68 and 77 degrees, is recommended.

Cogentin may cause sleepiness or dizziness. Do not drive or operate machinery until you determine how this medication will affect you. 

Side Effects of Cogentin 

Some people experience side effects when taking Cogentin. Certain adverse effects are more common than others, and some can be severe.

Common Side Effects

The most common side effects when taking benztropine are:

• Constipation
• Dry mouth
• Loss of appetite
• Nausea
• Trouble urinating or painful urination
• Vomiting

Talk to your healthcare provider if these effects are bothersome or persist over time. Changing the dose may help, or they may switch you to a different medication.

Severe Side Effects

Some benztropine side effects can be serious, including:

• Confusion
• Depression
• Fever
• Hallucinations or delusions
• Rapid or irregular heartbeat
• Skin rash
• Vision changes
  

Precautions and Contraindications for Cogentin

Individuals who tend to get an increased heart rate (tachycardia) or have an enlarged prostate (prostatic hypertrophy) should be monitored closely when taking Cogentin. This medication should also be used with caution in children over the age of three and adults aged 65 or older.

Cogentin is not advised for people with tardive dyskinesia or angle-closure glaucoma. It should also not be taken by children under the age of three or individuals who are hypersensitive to any ingredient in the Cogentin injection.

It's unknown whether Cogentin is safe to use during pregnancy. So, let your healthcare provider know if you are pregnant and they want to prescribe this drug.

Warnings and Interactions With Cogentin

Cogentin can lead to serious health issues as well as drug interactions. This includes:

Allergic Reaction

Allergic reactions may be mild or serious. Mild reactions include skin rashes that may go away if the dosage is decreased. Severe reactions can include swelling of the face and throat, trouble breathing, and hives. If you have a reaction, call your healthcare provider.

Heat Stroke

Cogentin can interfere with the body's ability to sweat. This can increase your risk for heat stroke, particularly when taking other drugs with anticholinergic effects, when it is very hot outside, or when engaged in strenuous exercise. Staying well-hydrated and avoiding excessive sun exposure may help.

Mental Health Effects

This medication may lead to symptoms of confusion, excitement, or hallucinations. These risks tend to be more serious in older adults. They can also be serious for people who are taking larger doses of Cogentin or with a history of mental health conditions.

Muscle Weakness

In large doses, this medication can result in mental confusion, excitement, or the weakness of or inability to move certain muscle groups. If you experience any of these effects, talk to your healthcare provider about lowering your dose.

Interactions

Cogentin may interact with certain drugs, such as antipsychotic drugs and tricyclic antidepressants. In some cases, these interactions have been fatal. Therefore, it's important that you tell your physician about any other medications you are taking.

Also tell your provider about any supplements, herbs, or vitamins that you take. Any of these can potentially interact with this medication or might change the way the drug works in your body. When mixed with alcohol, Cogentin can increase your feelings of drowsiness.