High doses of tiotropium may lead to anticholinergic signs and symptoms. However, there
were no systemic anticholinergic adverse effects following a single inhaled dose of up
to 282 mcg tiotropium in 6 healthy volunteers. In a study of 12 healthy volunteers,
bilateral conjunctivitis and dry mouth were seen following repeated once-daily inhalation
of 141 mcg of tiotropium.
Accidental Ingestion
Acute intoxication by inadvertent oral ingestion of SPIRIVA capsules is unlikely since it
is not well-absorbed systemically.
A case of overdose has been reported from postmarketing experience. A female patient was
reported to have inhaled 30 capsules over a 2.5 day period, and developed altered mental
status, tremors, abdominal pain, and severe constipation. The patient was hospitalized,
SPIRIVA HandiHaler was discontinued, and the constipation was treated with an enema. The
patient recovered and was discharged on the same day.
No mortality was observed at inhalation tiotropium doses up to 32.4 mg/kg in mice,
267.7 mg/kg in rats, and 0.6 mg/kg in dogs. These doses correspond to 7300, 120,000,
and 850 times the recommended human daily inhalation dose on a mg/m2 basis, respectively.
These dose multiples may be over-estimated due to difficulties in measuring deposited doses
in animal inhalation studies.