Tiotropium

Question 1

What are other drugs in the same class as tiotropium?

Answer 1

Ipratropium

Question 2

What is tiotropium?

Answer 2

antimuscarinic bronchodilator

Question 3

What is tiotropium used for?

Answer 3

the long term management of COPD

Question 4

What is the mechanism of action of tiotropium?

Answer 4

Long acting muscarinic antagonist (competitive reversible) which inhibits M receptors in smooth muscle resulting in bronchodilation.

Tiotropium demonstrates kinetic receptor subtype selectivity by dissociating slower from the M1 and M3 subtypes. –> longer duration of action

Question 5

What are the important pharmacokinetic and pharmacodynamic properties of tiotropium?

Answer 5

Half life: 35 hours
Absorption: unaffected by food
Volume of distrib: 32L/kg
Metabolites: inactive
Excretion: Mostly renal.

Question 6

What are the precautions regarding tiotropium?

Answer 6

not suitable for acute bronchospasm relief
Pregnancy class B1
Renal impairment < 50mL/min
Family history of severe long sightedness
Asian/hispanic ethnicity, females, lactation, children.

Question 7

What are the contraindications regarding tiotropium?

Answer 7

Hypersensitivity to atropine (muscarinic agonist) or its derivatives

Question 8

What are the adverse effects regarding tiotropium?

Answer 8

Common: dry mouth, GI motility disorders (constipation, diarrhoea), cough, headache.

Less common: nausea, gastro-oesophageal reflux, dysphagia (difficulty swallowing), tachycardia, throat irritation, bronchospasm (including paradoxical) urinary retention, angle
closure glaucoma

Rare: dental caries, dry skin.

Question 9

What are the main interactions with tiotropium?

Answer 9

Increased risk of anti-muscarinic side effects if taken with

• tricyclic antidepressants,
• antihistamines (except for topical, inhalation administration),
• Clozapine,
• Codeine,
• Disopyramide,
• MAOIs,
• Nefopam,
• Antagonises the effects of GI activity of Domperidone, Metoclopramide and
  parasympathomimetics
• Reduces effects of Haloperidol and sublingual nitrate tablets,
• Reduces the absorption of Levodopa
• Reduces plasma [phenothiazines] & increases risk of antimuscarinic side effects.
• Memantine enhances the effects of antimuscarinics
• Avoid concomitant use with atazanavir, cyclosporine, fosamprenavir, indinavir,
  itrazconazole, lopinavir, ritonavir, saquinavir, tipranavir, verapamil

Question 10

What are the alarm bells regarding tiotropium?

Answer 10

Take caution when

-using in patients with prostatic hyperplasia, bladder outflow obstruction as
one of the side effects is urinary retention.

• patients susceptible of angle closure glaucoma which has been reported with nebulised ipratropium particularly when nebulised salbutamol and other beta 2
  agonists are also given.
• Patient’s eyes need to be protected from the nebulised drug or
  powder.