Cycloset (bromocriptine mesylate) is a newly approved drug for controlling blood sugar in type 2 diabetes. Bromocriptine has previously been approved for Parkinson’s disease and pituitary tumors. Type 2 diabetes treatment is a new indication for this drug.
Cycloset has been proven effective in clinical trials and was also the subject of a 52-week safety trial. The safety trial is part of a new FDA guideline for diabetes medications. New diabetes drugs must now be clinically proven not to cause cardiovascular problems such as heart attack and stroke, and Cycloset passed this test.
Determining Cycloset Dosages
Cycloset is available in 0.8 mg pills. It should be taken within two hours of waking in the morning, and with food to reduce nausea.
Cycloset dosages are gradually increased from a low initial dose to a higher therapeutic dose, which varies among patients, a process called titration. A prescription for Cycloset starts with a single 0.8 mg pill. The patient takes one pill per day for a week, then adds a second pill for a dosage of 1.6 mg. The pills should be taken at the same time.
If this dosage is tolerated after a week, a third pill can be added for a dosage of 2.4 mg. The process of adding one pill per week is continued until the patient is taking six pills per day (4.8 mg), unless serious side effects occur. After the titration procedure is complete, the patient will take the highest tolerated dosage, recommended to be between 1.6 mg and 4.8 mg (two to six pills).
Side Effects of Too-High Dosages
The three most serious side effects of Cycloset are low blood pressure (hypotension), psychotic symptoms, and somnolence (drowsiness).
Hypotension can cause lightheadedness and fainting (syncope). This symptom is generally seen in patients who are also taking a medication to treat high blood pressure. In trials, this side effect was rare, occurring in less than 2% of patients (less than 1% after subtracting the incidence in placebo patients).
Psychosis is a serious mental condition in which a person loses touch with reality. It may involve hallucinations (sensing things that are not there, such as hearing voices) or delusions (firmly held, obviously false beliefs). Cycloset is not recommended for patients already suffering from a psychotic disorder such as schizophrenia. In trials, Cycloset has not been reported to have caused psychotic symptoms in any patients, but the warning remains because the active ingredient bromocriptine is associated with psychosis.
Somnolence resulting from Cycloset usually improves with time. Patients taking this medication should refrain from driving or operating heavy machinery after each Cycloset dosage increase until they know how the medication affects them.
The most common side effect of Cycloset is nausea, occurring in about one fourth of patients. Taking Cycloset with food may reduce this symptom. Other reported side effects are nose and sinus irritation, asthenia (weakness), dizziness, and amblyopia (decreased vision in one eye, or “lazy eye”). Cycloset is a dopamine agonist (i.e. it increases the activity of the neurotransmitter dopamine), and should usually not be combined with other dopamine agonists or with antipsychotics (which reduce dopamine activity).
- FDA label for Cycloset
- “VeroScience Announces FDA Approval Of Cycloset For Treatment Of Type 2 Diabetes.” Medical News Today, May 7, 2009.