Trade name(s): Symbicort, DuoResp Spiromax, Vannair Drug Class: Bronchodilator
Theraputic use: This is used as a dual reliever and preventer strategy. this is achieved through budesonide and formoterol (short onset laba) formoterol should not be used on its own
Pharmacological action of formoterol (budesonide has its own doc): It acts as a long acting short onset agonist for the beta receptors in the lungs.
Pharmacokinetics:
- Absorption The bronchodilating effect is dose dependent, with an onset of effect within 1-3 minutes after inhalation. The duration of effect is at least 12 hours after a single dose.
- Distribution Plasma protein binding is approximately 50% for formoterol. Volume of distribution is about 4 L/kg for formoterol
- Metabolism Formoterol is inactivated via conjugation reactions (active O-demethylated and deformylated metabolites are formed, but they are seen mainly as inactivated conjugates).
- Excretion The major part of a dose of formoterol is eliminated by metabolism in the liver followed by renal excretion. After inhalation of formoterol via Turbuhaler, 8-13% of the delivered dose of formoterol is excreted unmetabolised in the urine. Formoterol has a high systemic clearance (approximately 1.4 L/min) and the terminal elimination half-life averages 17 hours.
Indications: Asthma and COPD Contraindications: Hypersensitivity to budesonide, formoterol or to lactose. Precautions: should only be used where ICS are inadequate and to be used in conjunction with ICS
Adverse reactions:
- Common headache, tremor, dizziness, nausea, muscle cramps
- Uncommon tachycardia, palpitations, cardiac arrhythmiac, angina pectorialis, sleep disturbance, hypersensitivity, hypokalaemia, hyperglycaemia, taste disturbance, variations in blood pressure.
- Rare Agitation, restlessness
Interactions: There have been no specific interactions studies carried out with oxis 6 turbhaler which is formoterol only
However some interactions may be observed with: Beta-blockers: As Formoterol is a long acting beta agonists a beta blocker can negate effets and even lead to bronchospasm.
Xanthine derivatives Hypokalaemia may result from ß2 agonist therapy and may be potentiated by concomitant treatment with xanthine derivatives corticosteroids and diuretics
Medicines effecting cardiovascular function There is a theoretical risk that concomitant treatment with other medicines known to prolong QTV-interval may give rise to a pharmocodycamic interaction with formoterol and increase possible risk of CVS effets and such as ventricular arrthymias. these medicine include certain antihistamines certain antiarrhythmics, erythromycin phenothiazines and tricyclic antidepressants.
Other sympathomimetics As formoterol is a sympathomimetic it could have a cumulative effect with other sympathomimetics
Dosing/Current guidelines:
Oxis inhaler Asthma Dosage of turbhaler should be individualised for each patient and should be used at the lowest effective dose
Children (6yrs<): 1-2 inhalations one or twice daily a daily dose of 24 µg should not be exceeded
Adults: 2 inhalations once or twice daily up to four once or twice. 48µg should not be exceeded Can be administered morning or night (to prevent nocturnal asthma) one to two inhalations can be take pre exercise to prevent bronchospasm
COPD 2 inhalations once or twice daily up to four once or twice. 48µg should not be exceeded
Monitoring: Overdose: Likely to be the same is overcooking dose
Treatment of OD: Supportive treatment may be needed
Beta-blockers should be used with care as they could induce bronchospasm.
Pregnancy No exact warning but it shoudl only be given is the expected benefit is greater than any possible risk to child.
What to tell patients: Explain how to take whatever inhaler is in question
Comments/Observations/notes: