Orciprenaline
Indications
Orciprenaline is used for:
Chronic management of reversible airways obstruction, Bradycardia
Adult Dose
Oral
Chronic management of reversible airways obstruction
Adult: As sulfate: 20 mg 3 or 4 times daily.
Bradycardia
Adult: As sulfate: Up to 240 mg daily in divided doses.
Inhalation
Acute bronchospasm
Adult: As sulfate: Metered-dose inhaler releasing 750 mcg per inhalation: 1 or 2 inhalations; repeat if necessary. Max: Up to 12 inhalations in 24 hr. As 5% soln from a hand nebuliser: 10 inhalations. With a nebulising device e.g. intermittent positive-pressure breathing (IPPB) apparatus: 0.2-0.3 ml of a 5% solution diluted up to 2.5 ml physiological saline, administered not more often than every 4 hr.
Intravenous
Bradycardia
Adult: As sulfate: 250-500 mcg by slow IV inj.
Child Dose
Oral
Chronic management of reversible airways obstruction
Child: As sulfate: Up to 1 yr: 5-10 mg tid; 1-3 yr: 5-10 mg 4 times daily; 3-12 yr: 40-60 mg daily in divided doses.
Inhalation
Acute bronchospasm
Child: As sulfate: Metered-dose inhaler: >12 yr: 1 or 2 inhalations (750 mcg); repeat if necessary after not <3 hr. Max in 24 hr: <6 yr: Up to 4 inhalations; 6-12 yr: Up to 8 inhalations; >12 yr: Up to 12 inhalations. Nebuliser: Infants and children: 0.01-0.02 ml of 5% solution; min dose: 0.1 ml; max dose: 0.3 ml diluted in 2-3 ml normal saline every 4-6 hr or more frequently if necessary.
Renal Dose
Administration
May be taken with or without food.
Contra Indications
Cardiac arrhythmias associated with tachycardia.
Precautions
CV disease (e.g. arrhythmia, hypertension, CHF), DM, glaucoma, hyperthyroidism, hypokalaemia, seizure disorders. Pregnancy and lactation.
Pregnancy-Lactation
Interactions
Effects may be antagonised by β-blockers e.g. propranolol. Duration of bronchodilation may be increased with inhaled ipratropium. Increased adverse effects with MAOIs, TCAs, sympathomimetics.
Potentially Fatal: Increased risk of malignant arrhythmias with halothane.
Adverse Effects
Side effects of Orciprenaline :
Tachycardia, nervousness, increased serum glucose, increased potassium levels, tremor, palpitation, headache, dizziness, insomnia, nausea, vomiting, bad taste, heartburn, xerostomia, trembling, muscle cramps, weakness, coughing, pharyngitis, increased diaphoresis, paradoxical bronchospasm, hypertension, chest pain, angina, drowsiness, diarrhoea, taste change.
Mechanism of Action
Orciprenaline is a direct acting sympathomimetic with predominantly β2-adrenoceptor stimulant activity. It has minimal effect on heart rate.