tiotropium
Last reviewed 02/2021
Tiotropium
- is structurally related to ipratropium bromide
- is an antagonist of M1, M2 and M3 muscarinic receptors - however it dissociates more slowly from the M1 and M3 subtypes than from the M2 subtype
- has a long duration of action (terminal elimination half-life is 5-6 days), which allows it to be taken once daily
- with regular once-daily dosing, the maximum effect of tiotropium on forced vital capacity (FVC) may take more than a week to develop fully
- seems to be more effective than ipratropium bromide (40µg four times daily) in terms of reduction in exacerbations, but whether it is more effective in improving trough FEV1 is unclear
- the most common
side effect is dry mouth
- dry mouth was the most common adverse effect of
tiotropium (about 14% of patients) in one-year studies, but it was usually mild
and often resolved as treatment continued (1)
- more patients developed dry mouth with tiotropium than with ipratropium (12.1% vs. 6.1%) in comparative studies
- other common adverse effects of tiotropium (affecting 1-10% of patients) include constipation, candidiasis, sinusitis and pharyngitis
- uncommon adverse effects (0.1-1.0% of patients) include allergic reactions,
urinary difficulty, urinary retention and tachycardia (1)
- there have also been isolated reports of atrial fibrillation and supraventricular tachycardia
- care should be taken to avoid co-prescription of preparations containing anticholinergics (1)
- no consistent difference in health outcomes has been found between long-acting b2-agonists and tiotropium. Therefore, drug choice depends on individual factors and cost (1)
- dry mouth was the most common adverse effect of
tiotropium (about 14% of patients) in one-year studies, but it was usually mild
and often resolved as treatment continued (1)
The Drug and Therapeutics review concluded that "..To determine tiotropium's place in practice, trials using clinically relevant endpoints are needed to compare it with ipratropium (including 80µg four times daily) and with oxitropium twice daily".
A meta-analysis (3) however concluded that:
- in patients
with stable chronic obstructive pulmonary disease (COPD), tiotropium reduces exacerbations
and hospital admissions, and improves health related quality of life
- tiotropium reduced COPD exacerbations and related hospitalisations compared to placebo and ipratropium
- improved health-related quality-of-life and symptom scores among patients with moderate and severe disease, and may have slowed decline in FEV1
The summary of product characteristics must be consulted before prescribing this drug.
Reference:
- MeReC Briefing 2006;33:1-8.
- Drug and Therapeutics Bulletin (2003);41:9-16.
- Barr RG et al. Inhaled tiotropium for stable chronic obstructive pulmonary disease. Cochrane Database Syst Rev 2005;(2):CD002876