Antipsychotic medications are commonly used to treat psychotic disorders like schizophrenia and bipolar disorder.
However, these drugs often cause side effects like elevated prolactin levels, which can negatively impact long-term health.
A new study analyzed medical records to compare prolactin levels between patients taking different antipsychotics.
It found risperidone and amisulpride caused the greatest prolactin increases, especially in women.
The findings highlight the importance of monitoring prolactin during antipsychotic treatment to prevent complications.
Key Facts:
- 70% of patients in the study developed hyperprolactinemia (high prolactin) while taking antipsychotics
- Risperidone and amisulpride led to higher prolactin than blonanserin and olanzapine
- Women generally had greater prolactin increases than men
- High prolactin can cause sexual dysfunction, bone loss, and possibly breast and cardiovascular disease
- Checking prolactin levels regularly allows intervening to prevent long-term consequences
Source: Clinical Psychopharmacology and Neuroscience 2023
The Risks of Antipsychotic-Induced Hyperprolactinemia
Antipsychotic medications play an indispensable role in managing severe mental illnesses like schizophrenia, bipolar disorder, and psychotic depression.
By blocking dopamine receptors in the brain, these drugs reduce hallucinations, delusions, and disorganized thinking.
However, dopamine is also involved in regulating prolactin secretion, so antipsychotics often elevate prolactin levels as an adverse effect.
Prolactin is a hormone produced by the pituitary gland that enables breast development and milk production.
Normal levels fluctuate but remain between 3-30 ng/ml in most adults.
Hyperprolactinemia refers to sustained prolactin elevations above the normal range, typically over 25 ng/ml.
It affects up to 70% of individuals taking antipsychotics long-term.
While prolactin increases may not produce immediate symptoms, persistently high levels can cause significant health problems.
By inhibiting other pituitary hormones, hyperprolactinemia suppresses the reproductive system, leading to sexual dysfunction, menstrual irregularities, infertility, and bone mineral loss over time.
Prolonged exposure has also been associated with an increased risk of certain cancers and cardiovascular disease.
Recognizing these concerns, the authors investigated prolactin outcomes in patients taking some of the most commonly prescribed antipsychotic medications.
Prolactin Levels & Antipsychotic Drugs: Different Effects
The researchers utilized an extensive clinical data warehouse containing electronic medical records from a large university hospital system in South Korea.
They identified 260 patients diagnosed with schizophrenia, bipolar disorder, or other psychotic conditions who were prescribed one of four antipsychotic agents: risperidone, amisulpride, blonanserin, or olanzapine.
After excluding patients on multiple antipsychotics or with pituitary disorders, the final analysis included 117 subjects (69 women, 48 men).
Around half had schizophrenia while others had bipolar or related diagnoses.
The researchers obtained the antipsychotic dose and serum prolactin level measured closest to the start of treatment for each patient.
Based on evidence that prolactin exceeding 25 ng/ml often leads to symptoms, they defined hyperprolactinemia as prolactin over this threshold.
Patients with levels from 25-50 ng/ml had mild hyperprolactinemia, 50-100 ng/ml moderate, and over 100 ng/ml severe.
Higher doses typically cause greater prolactin elevations.
To account for this, the authors converted the medication doses into equivalent amounts of chlorpromazine, an older antipsychotic.
Prolactin Increased Most With Risperidone and Amisulpride
Across all subjects, the average prolactin level was 65 ng/ml, meeting criteria for mild hyperprolactinemia.
70% of patients developed hyperprolactinemia, indicating it is a common antipsychotic side effect.
Prolactin was higher in women at 87 ng/ml versus 33 ng/ml in men.
The breakdown by medication showed:
- Risperidone: Average prolactin 80 ng/ml, 88% hyperprolactinemia
- Amisulpride: Average prolactin 122 ng/ml, 100% hyperprolactinemia
- Blonanserin: Average prolactin 50 ng/ml, 67% hyperprolactinemia
- Olanzapine: Average prolactin 43 ng/ml, 48% hyperprolactinemia
Risperidone and amisulpride clearly led to the greatest prolactin elevations, with blonanserin and olanzapine showing more modest effects.
Amisulpride stood out as causing severe hyperprolactinemia (over 100 ng/ml) in 70% of users.
Risperidone, blonanserin, and olanzapine led to severe hyperprolactinemia in 33%, 6%, and 13% of patients respectively.
These findings are consistent with previous studies indicating risperidone and amisulpride tend to increase prolactin the most out of widely used antipsychotics.
Female Patients Experience Greater Prolactin Increases
Further analysis found females had higher prolactin levels than males with risperidone, blonanserin, and olanzapine treatment.
The average prolactin in women taking these drugs was 86-109 ng/ml compared to 21-40 ng/ml in men.
However, there was no significant difference between sexes in the amisulpride group, with both around 130 ng/ml.
These results highlight females generally experience greater prolactin elevations from most antipsychotics.
Variations in body composition, hormones, and medication metabolism likely contribute.
Consequently, extra vigilance monitoring prolactin is warranted in women using antipsychotics to avoid long-term reproductive and bone effects.
Regularly Checking Prolactin Levels Recommended for Users of Antipsychotics
This study provides valuable real-world data using medical records from one health system.
While it has limitations, the findings reinforce the need to regularly check prolactin levels in patients taking antipsychotic medications.
This allows intervening promptly if hyperprolactinemia develops by switching drugs, reducing doses, or adding treatments that normalize prolactin.
Risperidone and amisulpride appear most likely to raise prolactin, particularly at higher doses.
However, no antipsychotic is risk-free, and individual responses vary.
Olanzapine and blonanserin may represent safer options regarding hyperprolactinemia.
Quetiapine, aripiprazole, lurasidone, and brexpiprazole also tend to cause minimal prolactin elevations.
Ultimately, the benefits of antipsychotics for treating serious psychiatric illnesses generally outweigh the risks of managing hyperprolactinemia.
Still, measuring prolactin provides vital information to enhance long-term health outcomes.
This requires improving awareness among psychiatrists about monitoring recommendations and best practices.
With proper vigilance and treatment adjustments when indicated, patients can continue receiving these life-changing medications safely.
References
- Study: Prolactin level changes according to atypical antipsychotics use: a study based on clincial data warehouse
- Authors: Suhyung Kim et al. (2023)
