redrose asked
In April 2017 my metoprolol succinate was changed to bisoprolol fumurate 5 mg, and then in April 2018 the bisoprolol fumurate was increased to 10 mg. For about 10 months I've had lack of energy and memory problems. The memory problems became very apparent to me. Can bisoprolol fumarate cross the blood-brain barrier? Could this medication be causing my memory problems and lack of energy?
At a glance
- Bisoprolol is associated with causing a 'mental fog' and mild memory loss.
- If these side effects are occurring, a change in drug may be appropriate and you should discuss it with your doctor.
Answer
Bisoprolol is classified as a 'beta-blocker', a fairly diverse class of drugs with important pharmacologic and pharmacokinetic differences between them.
Three of the main differentiating factors are:
- Lipid solubility
- Cardioselectivity
- Sympathomimetic activity
Bisoprolol 'lipid-soluble' and is associated with a feeling of "mental fog". I discuss this further in the next sections.
Beta-Blockers And Lipid Solubility
When it comes to side effects, especially cognitive impairment or sedation, lipid solubility is most likely the key characteristics to be aware of and is what I will be discussing here.
In general, drugs with high lipid solubility readily cross the blood-brain barrier and thus can cause related side effects. Lipid solubility also has a significant effect on metabolism.
Beta-blocker medications run the range from low to high lipid solubility. Two of the highest lipid-soluble ones are propranolol and metoprolol. A low lipid-soluble example is atenolol.
Bisoprolol is generally classified on the low end of the lipid-soluble range but does nonetheless but have associated properties.
Bisoprolol Side Effects
As mentioned, lipid solubility can affect many different characteristics of a drug, including metabolism and side effects.
As bisoprolol does have some lipid-soluble properties, it can cross the blood-brain barrier. This often is associated with central nervous system (CNS) side effects, such as:
- Sedation
- "Mental fog"
- Dizziness
- Headache
- Depression
- Vivid dreams
According to the prescribing information for bisoprolol, the incidence of these CNS effects is:
- Sedation/Fatigue (8%)
- Dizziness (3%)
- Headache (10%)
- Depression (<0.2%)
- Dreams (reported)
- Cognitive Impairment (reported)
The extent or existence of memory loss or significant cognitive/memory impairment on beta-blockers like bisoprolol is controversial.
A variety of studies have reported these effects but many others have concluded that there are no long term effects and associated symptoms are by-products of the sedative nature of the drugs.
Final Words
The side effects you described in your inquiry are certainly possible with bisoprolol and have been reported. It is important to discuss them with your doctor and discuss the best course of medication therapy for you.
References
- Cognitive effects of beta-blockers. ResearchGate
- Neuropsychological Side Effects of ß-Blockers. JAMA
- Use of Beta-Blockers and Risk of Dementia in Elderly Patients. PsychiatryOnline
- The influence of beta-blockers on delayed memory function in people with cognitive impairment. PubMed
- Zebeta Prescribing Information. AccessFDA
- Beta-blockers in Cardiovascular Medicine. JAPI
- Contemporary Use of β-Blockers: Clinical Relevance of Subclassification. ScienceDirect
- Basic pharmacokinetics of bisoprolol, a new highly beta 1-selective adrenoceptor antagonist. PubMed
- Characteristics of compounds that cross the blood-brain barrier. PubMed
- Lipid-soluble and water-soluble beta-blockers. Comparison of the central nervous system depressant effect. PubMed
