Medicine & Research

Cognitive Impairment

By Ellen Whipple, Pharm.D.
Cognitive impairment is a common problem associated with multiple sclerosis, and affects the ability to think, reason, concentrate, or remember. An estimated 40-70 percent of all persons with MS suffer from some degree of cognitive impairment. Typically, cognitive impairment is more common in patients with a progressive disease course, compared to patients with relapsing-remitting one (50-60 percent vs. 35-45 percent, respectively).

According to Dr. Ben Thrower, medical director of the MS Institute at the Shepherd Center, “cognitive impairment can also be observed in patients with both clinically isolated syndrome and radiographically isolated syndrome, and up to 20 percent of patients with benign multiple sclerosis experience cognitive impairment.” Cognitive impairment tends to be more severe in those who have had MS for a longer time and those with signs of permanent neurological damage. Cognitive impairment is not absent, however, from patients with early disease.

Because there are many factors that may cause or exacerbate cognitive impairment in MS patients, there are currently no FDA-approved products to treat MS-related cognitive impairment. According to Dr. Thrower, medications are sometimes the offending agent and can worsen cognitive impairment. Dr. Thrower explained, “changing medication regimens can sometimes improve the symptoms of cognitive impairment.” Additional factors that may exacerbate cognitive impairment include overexertion and heat.

Anticholinergic medications – perhaps the most common cause of cognitive impairment. Anticholinergic medications are one of the most common causes of acute and chronic cognitive impairment in patients both with and without MS. Anticholinergic medications are a class of drugs that block the action of the neurotransmitter acetylcholine in the brain.

They are used to treat many diseases including asthma, incontinence, gastrointestinal cramps, muscular spasms, depression, and sleep disorders. Anticholinergic medications frequently cause confusion, memory loss, worsening of mental function, and other cognitive effects. Elderly patients are generally more susceptible to the cognitive adverse effects of anticholinergic medications compared to younger adults.

Examples of anticholinergic medications include:
• Trihexyphenidyl (Artane)
• Benztropine mesylate (Cogentin)
• Flavoxate (Urispas)
• Oxybutynin (Ditropan, Oxytrol)
• Scopolamine
• Hyoscyamine (Levsinex)
• Tolterodine (Detrol)
• Belladonna alkaloids
• Fesoterodine (Toviaz)
• Solifenacin (VESIcare)
• Darifenacin (Enablex)
• Propantheline (Pro-Banthine)

Medications that cross the blood-brain barrier

Any medication that crosses the blood-brain barrier has the potential to decrease cognition. Psychoactive drugs, antidepressants, and anticonvulsants can cause acute states of confusion. In addition, nonpsychoactive drugs such as histamine H2 receptor antagonists (used to reduce stomach acid), cardiac medications, and antibiotics may cause acute and chronic cognitive impairments. It is important to note that not all patients experience cognitive impairment as a result of these medications. Compared to young people, elderly people are more likely to develop cognitive impairment because of medications. Generally, patients susceptible to cognitive impairment with one medication are more likely to experience it with other medications as well.

Advice from the pharmacist

If you are experiencing cognition challenges, speak with your pharmacist. In many cases, medication regimens can be changed to minimize cognitive problems. For example, administering medications at certain times of the day, such as before bedtime, may help minimize cognitive issues. Pharmacists may also be able to simplify treatment regimens to avoid additional confusion. This can be accomplished by suggesting medications that can be given once daily rather than multiple times per day, screening for therapeutic duplications, and suggesting medications that can be used to treat more than one symptom.

If you are experiencing cognitive impairment (or have a complicated medication regimen), you may want to consider having medications blister-packed or using a weekly device to dispense medications. There are also reminder apps available on Google and the Apple Store that alert you when it is time to take medications. Additionally, take caution during the summer to limit physical activity and time spent outside in the heat. It is important to recognize signs of fatigue early, and to take sufficient breaks to prevent overexertion and worsening of cognitive function.