What is the role of Orciprenaline (metaproterenol) in treating asthma or Chronic Obstructive Pulmonary Disease (COPD)?

Role of Orciprenaline (Metaproterenol) in Asthma and COPD Management

Orciprenaline (metaproterenol) is an outdated bronchodilator that has been largely replaced by newer, more selective beta-2 agonists in the treatment of asthma and COPD due to its less favorable side effect profile and shorter duration of action.

Current Status in Treatment Guidelines

Modern respiratory guidelines no longer recommend orciprenaline (metaproterenol) as a first-line or even alternative treatment option for either asthma or COPD. The European Respiratory Society Task Force and other major respiratory societies have moved away from less selective beta-agonists like orciprenaline in favor of more selective agents 1.

For COPD Management:

• First-line bronchodilators now include:
  • Long-acting muscarinic antagonists (LAMAs) like tiotropium
  • Long-acting beta-2 agonists (LABAs) like salmeterol, formoterol
  • Combination LABA/ICS (inhaled corticosteroids) for patients with exacerbation history 2

For Asthma Management:

• Short-acting selective beta-2 agonists (e.g., albuterol/salbutamol) are preferred for rescue therapy
• Long-acting selective beta-2 agonists combined with inhaled corticosteroids are recommended for maintenance therapy

Historical Context and Limitations

Orciprenaline (metaproterenol) is a resorcinol derivative with less selectivity for beta-2 receptors compared to newer agents 3. This lower selectivity results in:

1. More pronounced cardiovascular side effects (tachycardia, palpitations)
2. Shorter duration of action requiring more frequent dosing
3. Greater potential for tremor and other systemic effects

Studies from the 1980s showed that while metaproterenol was effective as a bronchodilator, it had several limitations:

• Oral administration was associated with significant side effects including increased pulse rate and blood pressure 4
• When compared with newer agents, it showed no advantages in efficacy but had more side effects 3

Special Considerations

COPD-Specific Concerns:

• Beta-blockers are contraindicated in asthma but not in COPD, though selective beta-1 blockers (bisoprolol, metoprolol succinate, nebivolol) are preferred when necessary 1
• For COPD patients, anticholinergic agents may provide better bronchodilation than beta-agonists when patients are already on theophylline 5

Delivery Methods:

• If metaproterenol must be used in specific circumstances, inhaled delivery is preferable to oral administration due to:
  • Equal efficacy at lower doses
  • Significantly fewer systemic side effects 6, 7
  • More rapid onset of action

Current Recommendations

For patients with asthma or COPD requiring bronchodilator therapy:

1. For rescue therapy: Short-acting selective beta-2 agonists (salbutamol/albuterol) are preferred over metaproterenol
2. For maintenance therapy:
   • COPD: LAMA (tiotropium) and/or LABA, with addition of ICS for those with exacerbation history 2
   • Asthma: ICS with LABA for persistent symptoms

Conclusion

Orciprenaline (metaproterenol) has been superseded by more selective, longer-acting, and safer bronchodilators in the management of both asthma and COPD. Current guidelines from respiratory societies do not include it among recommended treatments, and its use should be avoided in favor of more modern alternatives with better efficacy and safety profiles.