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Side Effect: Confusion or Altered Consciousness

What is Confusion or Altered Consciousness?

Confusion or altered consciousness, refers to a state in which a person experiences a disturbance in their awareness, attention, and ability to think, reason, and remember. It can manifest in various ways, including difficulty concentrating, memory impairment, hallucinations, or delusions.

What does Confusion or Altered Consciousness look like?

The appearance of confusion or altered consciousness can differ depending on its underlying cause, severity, and duration. In general, people with confusion may:

Severe confusion may lead to delirium, a condition characterized by sudden onset with disorganized thinking and behavior.
The experience of confusion or altered consciousness can be distressing and frightening for the affected person, who may feel disoriented, agitated, anxious, or depressed. Some people may not be aware of their confusion and deny that anything is wrong, while others may feel embarrassed or ashamed of their behavior.

Confusion or Altered Consciousness

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Who gets Confusion or Altered Consciousness?

Patients with cancer can experience confusion or altered consciousness, particularly in advanced stages of the disease or during treatment. The causes of confusion or altered consciousness in patients with cancer can vary, and may be due to various factors, including age, dehydration, medications, chemotherapy, radiation, infection, nutritional deficiencies, metabolic imbalances, brain metastases, and neurological complications.

For example, Ifosfamide, a type of IV chemotherapy, may cause confusion if a metabolite known as “CAA” (chloracetaldehyde) begins to build up in the brain. This is more common if ifosfamide is given on consecutive days for five days in a row, and less common if ifosfamide is given on fewer days in a row.

Memory impairment is a common side effect from a class of medications known as benzodiazepines. Examples of these medications include:

Bloodstream infections can also be a serious cause of confusion or altered consciousness.

How to prevent Confusion or Altered Consciousness

To prevent confusion or altered consciousness in patients with cancer, healthcare providers should closely monitor medication use and adjust dosages as necessary, maintain adequate hydration and nutrition, and address underlying medical conditions that may contribute to confusion or altered consciousness, such as infections or electrolyte imbalances.
Healthcare providers can also implement strategies to promote patient comfort, such as providing a calm and familiar environment, avoiding sensory overload, and maintaining regular sleep-wake cycles.

How to treat Confusion or Altered Consciousness

When treating confusion or altered consciousness in patients with cancer, healthcare providers should first identify the underlying cause of the symptoms. For example, patients with brain metastases may benefit from radiation therapy or surgery to reduce pressure on the brain.

Additional interventions may include medication management, hydration, nutrition support, or psychological interventions, such as cognitive-behavioral therapy or supportive counseling.
Medications are not routinely used to treat confusion unless patients have very distressing symptoms, or the patient is a safety risk to themselves or others. If medication intervention is deemed necessary, commonly used medications include olanzapine (Zyprexa®), quetiapine (Seroquel®), and aripiprazole (Abilify®) which are designed to calm the person down and decrease agitation.


1) Bush SH, Lawlor PG, Ryan K, et al. Delirium in adult cancer patients: ESMO Clinical Practice Guidelines. Ann Oncol 2018;29(Suppl 4):iv143-iv165.

Created: February 20, 2024 Updated: March 7, 2024