Ventolin®: composition and pharmaceutical form
One dose of Ventolin® contains 100 micrograms or 200 micrograms of salbutamol as salbutamol sulfate. The medicine comes in two inhaled forms: a metered-dose inhalation aerosol as a suspension and a powder for inhalation.
The difference between the forms is not only in the device. The aerosol requires the breath to be coordinated with pressing the canister and, for those who find that hard, it is used with a spacer; for infants and small children there is the Babyhaler paediatric chamber. The powder for inhalation is delivered through a dedicated inhaler and is designed for a 200 microgram dose. Both forms are intended exclusively for inhalation.
How Ventolin® works
Salbutamol is a selective agonist of β2-adrenergic receptors. At therapeutic doses it stimulates the β2 receptors of bronchial smooth muscle, which leads to their relaxation.
In reversible airway obstruction the bronchodilator effect arrives quickly — within 5 minutes of inhalation — but does not last long, 4 to 6 hours. Hence the medicine's role: it relieves the attack, it does not treat the inflammation underlying asthma.
Indications
Both forms are used in bronchospasm and reversible airway obstruction in adults, adolescents and children aged 4 to 11; the powder for inhalation is also indicated for relieving asthma symptoms. The aerosol is used in infants and children under 4 as well.
The medicine can be used preventively — before physical exertion in exercise-induced asthma, and also before an expected contact with allergens that usually trigger an attack of breathlessness. Ventolin® is especially valuable in asthma of mild, moderate and severe course, but with one fundamental condition: its use must not delay the start of treatment with inhaled glucocorticosteroids.
Method of use and dosage
An attack is relieved with the minimum effective dose, and the preventive inhalation is taken 10–15 minutes before exertion or contact with the allergen. In none of its forms is salbutamol used more than four times a day.
| Situation | Dose |
|---|---|
| Aerosol, adults and adolescents, relief of bronchospasm | 100–200 micrograms, that is 1–2 inhalations |
| Aerosol, prevention before exertion or an allergen | two inhalations of 100 micrograms 10–15 minutes beforehand |
| Aerosol, children under 12 | 100 micrograms and, if needed, 200; long-term, up to 200 micrograms 4 times a day |
| Powder, adults and adolescents | 200 micrograms per dose; a maximum of 800 micrograms a day |
| Powder, children aged 4 to 11 | 200 micrograms if needed; long-term, 200 micrograms 4 times a day, a maximum of 800 |
| Powder, prevention | 200 micrograms 10–15 minutes before exertion or contact with the allergen |
The key signal is the need for an extra dose or a sudden need to raise the dose. That does not mean the medicine is "weak", but that the asthma has slipped out of control and a doctor must be consulted.
Contraindications
There are few restrictions, but one of them concerns obstetric practice.
- hypersensitivity to any component of the medicine;
- the aerosol is not used to prevent uncomplicated premature labour or in threatened miscarriage.
Special warnings and precautions
Bronchodilators must not be the only or the main treatment in severe or unstable asthma. Such patients need careful monitoring with assessment of respiratory function, in order to determine the risk of a severe attack and even of death; the doctor considers the maximum recommended doses of inhaled corticosteroids and, if necessary, adds oral ones. Raising the dose or the frequency of use of the medicine is permissible only under medical supervision.
When to see a doctor immediately
A growing need for bronchodilators, above all short-acting inhaled β2 agonists, means worsening asthma control. If the usual inhalation has started to work less strongly or is needed more often than normal, a doctor should be contacted without delay: in that situation the condition is assessed and strengthening the anti-inflammatory treatment is considered — raising the dose of inhaled corticosteroids or prescribing oral ones temporarily. Severe asthma exacerbations are treated by the accepted rules.
Heart, potassium and the composition of the medicine
- in thyrotoxicosis salbutamol is used with caution;
- β2 agonists, especially parenterally or in a nebuliser, may cause potentially severe hypokalaemia;
- in acute severe asthma the risk of hypokalaemia is higher — because of tissue hypoxia and simultaneous treatment with xanthine derivatives, steroids and diuretics; in such cases the potassium level is monitored;
- after the use of sympathomimetics an influence on the circulatory system is observed;
- rare cases of myocardial ischaemia linked to salbutamol have been described;
- patients with severe heart disease in the history — ischaemic heart disease, arrhythmias, severe heart failure — are warned to see a doctor with chest pain and other signs of worsening;
- particular attention is paid to breathlessness and chest pain: they may be of cardiac as well as respiratory origin;
- the medicine is not used in hereditary galactose intolerance, Lapp lactase deficiency and glucose-galactose malabsorption syndrome.
Drug interactions
Salbutamol must not be used at the same time as medicines that non-selectively block β-adrenergic receptors, for example propranolol.
The reason is direct: such agents act in the opposite direction and can cancel out the bronchodilator effect, and in a patient with asthma that turns into an attack. This is worth remembering if treatment for the heart, for hypertension or for migraine is prescribed in parallel — the doctor must be told that you use an inhaler.
Pregnancy and breastfeeding
The medicine is used in pregnant women only when the expected benefit to the mother outweighs the possible risk to the foetus. As with most medicines, data on the safety of salbutamol in early pregnancy are scarce, but in animal studies with very high doses some damaging effect on the foetus was noted. The influence of the freon-free HFA 134A propellant in the aerosol was studied separately — it had no effect on foetal development in animals.
Salbutamol is probably excreted in breast milk, so its use in breastfeeding women calls for particular judgement. Whether it has a harmful effect on the child is unknown, so prescribing it during breastfeeding is limited to cases where the expected benefit to the mother is greater than the possible risk to the child. There is no information on the influence of salbutamol on fertility in humans; in animals no undesirable influence on fertility was found.
Adverse effects
Most of the reactions are a direct continuation of the medicine's action on β2 receptors beyond the bronchi, so they are predictable.
- common: tremor of the skeletal muscles, headache, tachycardia;
- uncommon: palpitations, irritation of the mucosa of the mouth and pharynx, muscle cramps;
- rare: a fall in blood potassium, dilation of the peripheral vessels;
- very rare: heart rhythm disturbances, including atrial fibrillation, supraventricular tachycardia and extrasystoles;
- very rare: hypersensitivity reactions, among them angioedema, urticaria, bronchospasm, a fall in blood pressure and collapse;
- very rare: excessive excitability;
- very rare: paradoxical bronchospasm;
- frequency not known: myocardial ischaemia — from spontaneous reports after the medicine reached the market.
Paradoxical bronchospasm deserves separate mention: if after the inhalation breathing has not eased but worsened, the medicine must be stopped at once and help sought. A significant fall in blood potassium is due precisely to the stimulation of β2 receptors and is therefore more likely at high doses.
Overdose
Overdose most often shows itself as transient disturbances arising from the pharmacological action of β agonists. Hypokalaemia may develop after an overdose, so the potassium level is monitored.
There are reports of lactic acidosis both with high therapeutic doses and with an overdose of short-acting beta agonists. In an overdose, therefore, monitoring the serum lactate level may be indicated — a rise in the concentration leads to metabolic acidosis. Particularly telling is the situation where rapid breathing persists or intensifies even though other signs of bronchospasm, for example wheezing, are already receding.
How to get a prescription for Ventolin® online
Ventolin® is a prescription-only medicine, and it is not only about the inhaler itself: the doctor must be sure that the baseline asthma treatment is properly set up and that the bronchodilator is not standing in for anti-inflammatory treatment. During the online consultation the doctor will clarify how often attacks occur, assess how often you use the inhaler and go through any concomitant heart disease.
If the medicine is suitable, the doctor will issue an electronic prescription, choose the form — aerosol or powder — and explain at which signs you need to return to the doctor rather than raise the dose on your own.
