Salbutamol

Registered South African indications:

• Bronchospasm - severe
• Status asthmaticus
• To inhibit uncomplicated premature labour between 22-37 weeks of gestation

Contraindications

South African recommendations

• History of hypersensitivity to the active ingredient or any of its excipients
• Should not be used for threatened abortion
• For the indication of premature labour, salbutamol IV is contraindicated in the following conditions
  - At a gestational age <22 weeks
  - Intrauterine foetal death
  - Known lethal congenital or lethal chromosomal malformation
  - Any condition of the mother or foetus in which prolongation of the pregnancy is hazardous (including placenta praevia, antepartum haemorrhage, toxaemia of pregnancy)
  - In patients with pulmonary hypertension, valvular heart disease, pre-existing ischaemic heart disease or those patients with significant risk factors for ischaemic heart disease

Recommendations in other jurisdictions

Injection (inj)

• Hypersensitivity to the active ingredient or any of its excipients
• Non-IV formulations of salbutamol must not be used to arrest uncomplicated premature labour or threatened abortion

Solution for intravenous infusion (inf)

• Hypersensitivity to the active ingredient or any of its excipients
• Any condition at gestational age <22 weeks
• As a tocolytic agent for patients with pre-existing ischaemic heart disease or significant risk factors thereof
• Threatened abortion during first and second trimester
• Any condition of the mother or foetus in which prolongation of the pregnancy is hazardous
  - Severe toxaemia
  - Intrauterine infection
  - Vaginal bleeding resulting from placenta previa
  - Eclampsia or severe preeclampsia
  - Placental abruption
  - Cord compression
• Intrauterine foetal death
• Known lethal congenital or chromosomal malformation
• Pre-existing medical conditions with which a betamimetic would have an untoward effect
  - Pulmonary hypertension
  - Cardiac disorders such as hypertrophic obstructive cardiomyopathy or any type of obstruction of the left ventricular outflow tract, e.g. aortic stenosis
• Non-IV formulations of salbutamol must not be used to arrest uncomplicated premature labour or threatened abortion

Cautions

• Pregnancy
• Breastfeeding
• Renal impairment
• Hepatic impairment
• Monotherapy in severe or unstable asthma
• Diabetic patients
• Patients on pre-existing corticosteroid therapy
• Underlying severe cardiovascular disease (in bronchospasm)
  - Ischaemic heart disease
  - Arrhythmia
  - Severe heart failure
• Hyperthyroidism
• Thyrotoxicosis
• High therapeutic doses
• Rupture of membranes (tocolysis)
• Cervical dilation >4cm
• Pre-existing or suspected cardiac disease (in tocolysis)
  - Tachyarrhythmias
  - Heart failure
  - Valvular heart disease
• Caval compression
• History of heart disease
• Multiple pregnancies
• Fluid overload
• Maternal infection
• Pre-eclampsia

Forms avail. in SA and covered in this monograph: inj, inf

Dosages below include:

• South African registered indications and dosages
• Indications and dosages registered in other jurisdictions

South African registered indications and dosages

Bronchospasm - severe
- Associated with asthma or bronchitis

• IV (inj): 250μg OR 4μg/kg body mass, injected slowly
• IM/SC (inj): 500μg OR 8μg/kg body mass, 4hrly as required

Status asthmaticus

• IV (inf): Initial: 5μg/min, as an infusion with appropriate adjustments in dosage according to patient response; Maintenance: 3-20μg/min, as an infusion; Higher dosages have been used with success in those with respiratory failure
• IV (inj): 250μg OR 4μg/kg body mass, injected slowly
• IM/SC (inj): 500μg OR 8μg/kg body mass, 4hrly as required

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If salbutamol (inj, inf) must be given to an asthmatic patient in labour, it will inhibit uterine contractions. This effect can be counteracted by administration of natural or synthetic oxytocic drugs11,12

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Salbutamol (inj) may be diluted with water for injections B.P., sodium chloride injection B.P., sodium chloride and dextrose injection B.P., or dextrose injection B.P. These are the only recommended diluents and it is inadvisable to administer salbutamol (inj) in a syringe containing any other medication

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To inhibit uncomplicated premature labour
- Between 22-37 weeks gestation in patients with no medical or obstetric contraindication to tocolytic therapy

Treatment with salbutamol (inj, inf) should only be initiated by medical practitioners experienced in the use of tocolytic agents. Ideally, it should be carried out in facilities adequately equipped to perform continuous monitoring of maternal and foetal health status

• IV (inf): Initial: 10μg/min, as an infusion; Increase rate slowly every 10min until there is evidence of patient response shown by a diminution in strength, frequency or duration of contractions, until contractions cease; Maintenance: 10-45μg/min; Once uterine contractions have ceased the infusion rate should be maintained at the same level for 1hr and then reduced by 50% decrements at 6hrly intervals; Max duration of treatment: 48hrs
• IV (inj): 100-250µg, as a single injection; Dose may be repeated according to patient response; Max duration of treatment: 48hrs

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Salbutamol (inj, inf) should be administered as early as possible after the diagnosis of premature labour and after evaluation of the patient to eliminate any contraindications to the use of salbutamol (inj, inf). This should include an adequate assessment of the patient's cardiovascular status with continuous ECG monitoring throughout treatment. A maximum sustained maternal heart rate of 120 beats/min should not be exceeded

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Discontinue treatment should signs and symptoms of pulmonary oedema or myocardial ischaemia develop

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Salbutamol (inf) should be diluted with sodium chloride injection B.P., rather than sodium chloride and dextrose injection B.P. The contents of the ampoule of Salbutamol (inf) 5mg in 5ml must not be injected in the undiluted form

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Indications and dosages registered in other jurisdictions

Bronchospasm - severe

• IV (inj): 250μg OR 4μg/kg, injected slowly; Dose may be repeated if necessary
• IM/SC (inj): 500μg OR 8μg/kg body weight, 4hrly as required

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The use of salbutamol injection 500μg/ml for intravenous administration may be facilitated by dilution to 10ml with water for injection BP (final concentration of 50μg/ml) and 5ml of the diluted preparation (250μg/5ml) administered by slow intravenous injection

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• IV (inf): 3-20μg/min, as an infusion; Higher dosages have been used with success in those with respiratory failure

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Salbutamol for intravenous infusion is used to prepare an infusion solution. It should not be injected undiluted. The solution for intravenous infusion should not be administered in the same syringe or infusion as any other medication

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A suitable solution for infusion providing 10μg salbutamol/ml is prepared by diluting 5ml salbutamol (inf) to 500ml with an infusion solution such as sodium chloride and dextrose injection BP. Other suitable diluents are water for injections BP, sodium chloride injection BP or dextrose injection BP

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To arrest premature labour
- Between 22-37 weeks gestation in patients with no medical or obstetric contraindication to tocolytic therapy

Treatment with salbutamol solution for intravenous infusion should only be initiated by obstetricians/physicians experienced in the use of tocolytic agents. It should be carried out in facilities adequately equipped to perform continuous monitoring of maternal and foetus health status

• IV (inf): Initial: 10μg/min, as an infusion; Increase rate slowly every 10min until there is evidence of patient response shown by a diminution in strength, frequency or duration of contractions, until contractions cease; Maintenance: 10-45μg/min; Once uterine contractions have ceased the infusion rate should be maintained at the same level for 1hr and then reduced by 50% decrements at 6hrly intervals; Max duration of treatment: 48hrs

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Salbutamol (inf) should be administered as early as possible after the diagnosis of premature labour, and after evaluation of the patient to eliminate any contraindications to the use of salbutamol. This should include an adequate assessment of the patient's cardiovascular status with supervision of cardiorespiratory function and ECG monitoring throughout treatment

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If labour progresses despite treatment the infusion should be stopped

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The dose must be individually titrated with reference to suppression of contractions, increase in pulse rate and changes in blood pressure, which are limiting factors. These parameters should be carefully monitored during treatment. A maximum maternal heart rate of 120 beats per min should not be exceeded

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The recommended diluent is 5% dextrose for salbutamol solution for intravenous infusion

Paed. forms avail. in SA and covered in this monograph: inj, inf

Paed. dosages below include:

• South African registered indications and dosages
• Indications and dosages registered in other jurisdictions

South African registered indications and dosages

No information available

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No specific recommendations for children are provided

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Indications and dosages registered in other jurisdictions

Bronchospasm - severe

<12 years

• Not established for use

≥12 years

• See adult dosage

Pregnancy

• Caution
• Administration of salbutamol during pregnancy should only be considered if the expected benefit to the mother is greater than any possible risk to the foetus
• There is little published evidence of the safety of salbutamol in the early stages of human pregnancy, but in animal studies, there was evidence of some harmful effects on the foetus at very high dose levels

Breastfeeding

• Caution; not recommended
• As salbutamol is probably secreted in breast milk, its use in breastfeeding mothers is not recommended unless the expected benefits outweigh any potential risk. It is not known whether salbutamol has a harmful effect on the neonate so its use should be restricted to situations where it is felt that the expected benefit to the mother is likely to outweigh any potential risk to the neonate
• In such situations, the use of the inhaled route may be preferable although it is not known whether salbutamol has a harmful effect on the neonate

Fertility

• There is no information on the effects of salbutamol on human fertility. There were no adverse effects on fertility

Renal Impairment

• Caution; no information available
  No dosage adjustment required in patients on haemodialysis, peritoneal dialysis or continuous renal replacement therapy

Hepatic Impairment

• Caution; no information available

Elderly

• No dose adjustment recommended

Porphyria Information

• Not porphyrinogenic (NP)

Drugs in Sport

• Prohibited - At all times

Central Nervous System Disorders

• Tremor
• Headache
• Hyperactivity

Cardiovascular Disorders

• Tachycardia
• Palpitations
• Decrease in diastolic pressure
• Arrhythmias
  - Atrial fibrillation
  - Supraventricular tachycardia
  - Extrasystoles  
• Myocardial ischaemia
• Hypotension
• Peripheral vasodilatation

Respiratory Disorders

• Pulmonary oedema

Gastrointestinal Disorders

• Nausea and vomiting

Endocrine and Metabolic Disorders

• Hypokalaemia
• Hyperglycaemia
• Lactic acidosis

Musculoskeletal Disorders

• Muscle cramps

Immune, Blood and Lymphatic System Disorders

• Hypersensitivity reactions
  - Angioedema
  - Urticaria
  - Bronchospasm
  - Hypotension
  - Collapse

Other

• Slight pain or stinging on intramuscular use of undiluted injection

• Non-selective beta-blockers
• Propranolol
• Halogenated anaesthetics
• Systemic corticosteroids
• Antidiabetic therapy
• Potassium-depleting agents
• Diuretics
• Digoxin
• Methylxanthines

• Lung function
• Blood pressure
• Heart rate
• Blood glucose
• Serum potassium
• Serum creatinine
• ECG

Specific cases may require:

• Arterial or capillary blood gases
• Lactate levels

Additional observations

• Monitor asthma symptoms
• CNS stimulation

Monitoring considerations for tocolysis

• Salbutamol IV should be used with caution in tocolysis and supervision of cardiorespiratory function and ECG monitoring, should be performed throughout treatment. The following monitoring measures must be constantly applied to the mother and, when feasible/appropriate, to the foetus:
  - Blood pressure and heart rate; to minimise the risk of hypotension associated with tocolytic therapy, special care should be taken to avoid caval compression by keeping the patient in the left or right lateral positions throughout the infusion
  - ECG
  - Electrolyte and fluid balance - to monitor for pulmonary oedema; administration with a syringe pump as opposed to IV infusion will limit risk of fluid overload
  - Glucose and lactate levels - with particular regard to diabetic patients
  - Potassium levels - beta-agonists are associated with a decrease in serum potassium which increases the risk of arrhythmias
• Treatment should be discontinued if signs of myocardial ischaemia (such as chest pain or ECG changes) develop

Salbutamol is a selective beta- adrenoceptor agonist which acts on the beta- adrenoceptors of the bronchi and uterus. At therapeutic doses, it acts on the beta- adrenoceptors of bronchial muscle providing short-acting (4 to 6 hour) bronchodilation in reversible airways obstruction. 

Injection (per ml) 500μg

• Ventolin Injection (GSK) originator

Injection (per ml) 1mg

• Ventolin IV Solution (GSK) originator

Also available in the following forms: Syrup, tablet, solution, accuhaler, inhaler and nebulising solution.