Spiriva Respimat
Spiriva Respimat
Generic Name
Spiriva Respimat
Mechanism
Spiriva Respimat blocks acetylcholine at muscarinic M3 receptors in airway smooth muscle, preventing parasympathetic bronchoconstriction.
• Selective anticholinergic: preferentially binds to M3 over M2/M4, reducing cough reflex and bronchial hyperresponsiveness.
• Prolonged pulmonary residence: slow dissociation grants a 24‑hour bronchodilator effect while plasma exposure remains minimal, attenuating systemic anticholinergic side effects.
• Resulting benefits: decreased airway resistance, improved expiratory flow, and reduced dyspnea.
Pharmacokinetics
| Parameter | Characteristic | Clinical Notes |
| Absorption | ≈85 % of the delivered dose remains in the lung; < 2 % absorbed into plasma. | Minimal systemic exposure. |
| Distribution | Small volume of distribution; limited tissue penetration. | Reduced risk of extrapulmonary effects. |
| Metabolism | No significant hepatic metabolism; remains unchanged. | Not affected by CYP polymorphisms. |
| Excretion | Renal elimination of unchanged drug; half‑life ≈ 8 h in plasma, but pulmonary residence ≈ 4½ days. | Renal impairment → reduced clearance but dose adjustment rarely required. |
| Special Populations | Elderly & renal impairment show no clinically relevant pharmacokinetic changes. | Monitor for anticholinergic effects in older adults. |
Indications
- Chronic Obstructive Pulmonary Disease (COPD) – maintenance bronchodilation in adults; improves FEV1, reduces exacerbations.
- Asthma (adult) – adjunctive maintenance therapy in patients with persistent asthma; improves lung function when combined with inhaled corticosteroids.
- Note: not approved for acute exacerbations or as rescue therapy.
Contraindications
- Hypersensitivity to tiotropium bromide or any Respimat formulation ingredients.
- Pregnancy/Lactation – Category C; use only if benefits outweigh risks.
- Gastro‑intestinal obstruction, urinary retention, severe constipation, cholecystectomy history – contraindicated due to anticholinergic effect on GI and urinary function.
- QT interval prolongation – caution in patients with known QT prolongation or on concurrent QT‑prolonging drugs.
- Severe renal impairment – use with caution; monitor renal function.
Warnings
• Bronchospasm: rare but possible; treat as acute worsening.
• Anticholinergic toxicity: tachycardia, dry mouth, blurred vision; severe cases may require discontinuation.
Dosing
- Adult Dose: 2.5 µg once daily (full dose) via the Respimat inhaler.
- *Capacity*: 2 dose cartridges, each containing two reversible units; one full dose ≈ 0.5 mL spray.
- *Frequency*: *daily* (preferably same time each day).
- Children (6–11 y): 2.5 µg once daily if acceptable; data mainly in adults.
- Administration Technique
1. Shake the inhaler twice.
2. Hold the cap off the mouth and advance the tip.
3. Breathe out normally, inhale slowly, and hold breath for 10 s.
4. Wait 30–60 s between doses (if using both doses).
• Missed Dose: No double‑dose; resume next scheduled dose.
Adverse Effects
| Common | Serious | |
| Dry mouth, tonsillitis, mild cough, headache | Severe bronchospasm, aspiration pneumonia, urinary retention, visual disturbances (blurred vision), photophobia | |
| Gastro‑intestinal upset, constipation (rare) | QT prolongation, arrhythmias (rare) | |
| Mild muscle cramps (self‑limit) | Exacerbation of asthma/COPD severe enough to require hospitalization | |
| *Frequency* ≤ 10 % | < 1 % for serious events |
Risk‑Modification Tips
• Encourage hydration to mitigate xerostomia.
• Avoid concomitant anticholinergics (e.g., atropine, dextromethorphan).
Monitoring
- Pulmonary Function: FEV1, FVC 3–6 mo before initiation, then every 6–12 mo or when symptoms change.
- Symptom Review: dyspnea score, rescue inhaler use.
- Renal Function: serum creatinine at baseline; repeat if clinically indicated.
- Cardiac: pulse, blood pressure; QT interval if on other QT‑prolonging drugs.
- Aldosterone/Na⁺: not required routinely but monitor in patients with hyponatremia risk.
Clinical Pearls
- Single‑Dose Strategy: Use one full dose per inhaler rather than splitting; reduces dosing errors and inhalation technique variability.
- Device Refresh: Replace the Respimat cartridge every 8 days in young patients to maintain optimal plume, especially critical in COPD.
- Adjunct Therapy: Co‑administration with inhaled corticosteroids or LABAs is evidence‑based in asthma; for COPD, pair with LABA or LAMA/LABA combos for maximal benefit.
- Elderly Care: Start at 2.5 µg once daily; reassess for dry mouth, urinary retention, or falls after 1 mo.
- Research Note: Tiotropium’s slow reverse‑binding permits once‑daily dosing; a 5‑µg formulation is available in the EU but not FDA‑approved.
- Education Focus: Emphasize inhalation depth and holding breath; too rapid exhalation reduces delivery.
Take‑Home: Spiriva Respimat offers a once‑daily, soft‑mist delivery of tiotropium for reliable bronchodilation in COPD and asthma with minimal systemic exposure. Proper technique, patient education, and routine pulmonary function monitoring are key to optimizing outcomes and minimizing adverse effects.