Psychotropic drug-induced adverse drug reactions in 462,661 psychiatric inpatients in relation to age: results from a German drug surveillance program from 1993-2016.

BACKGROUND

Clinical practice suggests that older adults (i.e., ≥ 65 years of age) experience adverse drug reactions (ADRs) more often than younger patients (i.e., < 65 years of age). ADRs such as falls, extrapyramidal symptoms (EPS), metabolic disorders, sedation, and delirium are particularly worrisome and often associated with psychotropic drugs.

METHODS

This observational study investigated the risk for psychotropic drug-related ADRs in older (n = 99,099) and younger adults (n = 363,562) in psychiatric inpatients using data from the German pharmacovigilance program "Arzneimittelsicherheit in der Psychiatrie" (AMSP) from 1993-2016. The aim was to assess whether age influenced the risk of specific ADR types and if certain psychotropic drugs posed particular concerns.

RESULTS

The risk for ADRs did not differ between older and younger patients (relative risk 0.98, 95% confidence interval 0.92-1.05). However, older patients had a higher risk for delirium (2.35, 1.85-2.99), hyponatremia (3.74, 2.85-4.90), and orthostatic syncope (2.37, 1.72-3.26), as well as certain types of EPS, e.g., parkinsonism (1.89, 1.45-2.48) and Pisa-/metronome syndrome (3.61, 2.51-5.18). The risk for other ADRs, such as acute dystonia (0.20, 0.10-0.37), akathisia (0.47, 0.29-0.76), liver dysfunction (0.63, 0.48-0.82), weight gain (0.07, 0.04-0.14), sexual dysfunction (0.03, CI 0.00-0.25), and hyperprolactinemia/galactorrhea (0.05, 0.02-0.17) was significantly lower for older patients. Older patients treated with any type of antidepressant drug (1.33, 1.26-1.40)-especially selective serotonin reuptake inhibitors (1.57, 1.26-1.40) and selective serotonin-norepinephrine reuptake inhibitors (2.03, 1.80-2.29)-and lithium (1.74, 1.52-2.00) had a higher ADR risk than younger patients. Second-generation antipsychotic drugs had a lower (0.74, 0.71-0.77) and low-potency first-generation antipsychotic drugs a higher (1.19, 1.07-1.33) ADR risk in older patients. The risk for ADRs involving multiple drugs was higher in older patients (1.28, 1.22-1.34). ADRs in older patients were 6.4 times more likely to result in death.

CONCLUSIONS

Clinicians and pharmacists should be aware of the types of ADRs and high-risk drugs across age groups and provide appropriate monitoring. Pharmacovigilance is crucial in psychiatric patients of all ages and should not be neglected, even for drugs generally considered "safe".