SPIRIVA RESPIMAT

Dosage

Children: Paediatric dosing in micrograms is also highly variable based on the drug and the condition being treated. Refer to the BNF for Children for detailed dosing recommendations.

Adults: Dosage in micrograms varies widely depending on the specific medication and its indication. Consult relevant clinical guidelines or the BNF for precise dosing information.

Mechanism of action

The mechanism of action varies depending on the specific drug being measured in micrograms. For example, many drugs operate by binding to specific receptors or enzymes, leading to a physiological response. This can include agonistic or antagonistic effects on neurotransmitter systems, modulation of immune responses, or alteration of metabolic pathways.

Pharmacodynamics

Pharmacodynamics refers to the effects of the drug on the body, including the relationship between drug concentration and effect. Drugs measured in micrograms often have a steep dose-response curve, meaning small changes in dosage can lead to significant changes in therapeutic and adverse effects. The potency of such drugs is typically high, necessitating careful dosing and monitoring.

Pharmacokinetics

Pharmacokinetics involves the study of how the body absorbs, distributes, metabolizes, and excretes a drug. Drugs administered in microgram doses may exhibit rapid absorption and distribution, especially if given intravenously or sublingually. Metabolism often occurs in the liver, and excretion can be renal or via bile, depending on the drug's chemical properties. Understanding the pharmacokinetics is essential for optimizing therapeutic regimens and minimizing side effects.

Pregnancy

Consult a healthcare professional before use. Safety and efficacy during pregnancy have not been established.

Breast-feeding

Consult a healthcare professional before use. It is not known if this drug is excreted in human milk.

Storage

Store in a cool, dry place away from light. Keep out of reach of children.

Indications

• Maintenance treatment of chronic obstructive pulmonary disease (COPD)
• Severe asthma as an add-on therapy to inhaled corticosteroids and other controllers

Dosage

Children: For children aged 6-11 years: 5 micrograms once daily. For children aged 12-17 years, refer to BNF for Children for specific dosing guidance.

Adults: 1 capsule (18 micrograms) once daily by inhalation.

Mechanism of action

Tiotropium exerts its effects by selectively blocking the M3 muscarinic acetylcholine receptors in the bronchial smooth muscle. This blockade leads to relaxation of the bronchial muscles and dilation of the airways. The inhibition of these receptors prevents bronchoconstriction and facilitates easier breathing in patients with obstructive pulmonary diseases.

Pharmacodynamics

Tiotropium has a long duration of action due to its slow dissociation from the M3 receptors, allowing for sustained bronchodilation over a 24-hour period. The onset of action typically begins within 30 minutes of administration, with peak effects occurring around 3 hours post-dose. It significantly improves lung function, reduces exacerbation rates, and enhances exercise tolerance in patients with COPD.

Pharmacokinetics

Tiotropium is primarily absorbed through the lungs when inhaled, with approximately 20% of the delivered dose reaching systemic circulation. The drug undergoes minimal hepatic metabolism, primarily via cytochrome P450 enzymes, and is mainly excreted unchanged in the urine. The elimination half-life is approximately 5 to 6 days, which supports its once-daily dosing regimen.

Contra-indications

• Hypersensitivity to tiotropium, atropine or its derivatives
• Patients with narrow-angle glaucoma
• Patients with urinary retention

Adverse effects

• Cough
• Dizziness
• Dry mouth
• Headache
• Nausea
• Constipation
• Dysphonia
• Palpitations
• Skin reactions
• Stomatitis
• Urinary disorders
• Vision blurred

Interactions

• Clozapine: Unknown (additive effect)
• Second-generation antipsychotics: Unknown (additive effect)

Precautions

• Counsel patients on appropriate administration technique
• Warn against accidental contact with the eye due to risk of ocular complications
• Increased risk of dizziness affecting driving and skilled tasks

Pregnancy

Manufacturer advises only use if potential benefit outweighs risk.

Breast-feeding

No information available-manufacturer advises only use if potential benefit outweighs risk.

Storage

Store in a cool, dry place, away from direct sunlight.

Formulations

• {'name': 'Spiriva® Inhalation Powder', 'dose': '18 micrograms per capsule', 'route': 'inhalation'}
• {'name': 'Braltus® Inhalation Powder', 'dose': '13 micrograms per capsule', 'route': 'inhalation'}
• {'name': 'Nebuliser liquid', 'dose': 'Variable, refer to specific product information', 'route': 'nebulisation'}