- Quetiapine is not currently subsidised by the PBS (Pharmaceutical Benefits Scheme) for use by itself in BPII, meaning that this medication costs more than some others available. Quetiapine is PBS subsidised only when it is added to some other medications to prevent bipolar depression (e.g., lithium and sodium valproate).
Short-term
- Within the first 2-3 months of taking quetiapine, people experience the following side effects:
| Sleepiness/drowsiness | 17-19 in 100 people (17-19%) |
| Cognitive ‘dulling’ (i.e., difficulties remembering, slowed down thinking) | 5-16 in 100 people (5-16%) |
| Weight gain ≥ 7% of body weight* | 3-12 in 100 people (3-12%) |
*For a person weighing 70kg = ~ 5kg gain.
Weight gain is more common when taking higher doses of quetiapine and generally plateaus within first 10 weeks of treatment.
Mid-term
Within the first year of starting quetiapine, people may experience
the following side effects:
| Changes to their metabolism (e.g. blood sugar and cholesterol levels)* | 7-15 in 100 people (7-15%) |
| * It is unclear if these changes put people at higher risk of type II diabetes. | |
| Weight gain ≥ 7% of body weight* | 6-10 in 100 people (6-10%) |
| * For a person weighing 70kg = ~ 5kg gain. | |
| Headache | 11-14 in 100 people (11-14%) |
| Sleepiness/drowsiness | 6-7 in 100 people (6-7%) |
| Dry mouth | 3-6 in 100 people (3-6%) |
| Movement and muscle control problems | 2-3 in 100 people (2-3%) |
In most patients, these side effects are mild to moderate in intensity and become less severe over 1-4 months of treatment.
Long-term
- Regular, ongoing monitoring of blood sugar levels, cholesterol and weight gain is required. This usually involves urine and blood tests, and body weight measurement every 3-6 months.
Note many of the possible side effects of quetiapine depend on the dose taken.