It is also one of the most common medicines used in rescue inhalers (short-term bronchodilators to alleviate asthma attacks).As a β2 agonist, salbutamol also has use in obstetrics. Intravenous salbutamol can be used as a tocolytic to relax the uterine smooth muscle to delay premature labor. While preferred over agents such as atosiban and ritodrine, its role has largely been replaced by the calcium channel blocker nifedipine, which is more effective and better tolerated.Salbutamol has been used to treat acute hyperkalemia, as it stimulates potassium flow into cells, thus lowering the potassium in the blood. Adverse effects
The most common side effects are fine tremor, anxiety, headache, muscle cramps, dry mouth, and palpitation. Other symptoms may include tachycardia, arrhythmia, flushing of the skin, myocardial ischemia (rare), and disturbances of sleep and behaviour. Rarely occurring, but of importance, are allergic reactions of paradoxical bronchospasms, urticaria (hives), angioedema, hypotension, and collapse. High doses or prolonged use may cause hypokalemia, which is of concern especially in patients with kidney failure and those on certain diuretics and xanthine derivatives.Salbutamol metered dose inhalers have been described as the “single biggest source of carbon emissions from NHS medicines prescribing” due to the propellants used in the inhalers. Dry powder inhalers are recommended as a low-carbon alternative. Pharmacology
The tertiary butyl group in salbutamol makes it more selective for β2 receptors, which are the predominant receptors on the bronchial smooth muscles.
Vertebrate pesticide
4-Aminopyridine is also used under the trade name Avitrol as 0.5% or 1% in bird control bait. It causes convulsions and, infrequently, death, depending on dosage. The manufacturer says the proper dose should cause epileptic-like convulsions which cause the poisoned birds to emit distress calls resulting in the flock leaving the site; if the dose was sub-lethal, the birds will recover after 4 or more hours without long-term ill effect. The amount of bait should be limited so that relatively few birds are poisoned, causing the remainder of the flock to be frightened away with a minimum of mortality. A lethal dose will usually cause death within an hour. The use of 4-aminopyridine in bird control has been criticized by the Humane Society of the United States. Medical use
Fampridine has been used clinically in Lambert–Eaton myasthenic syndrome and multiple sclerosis. It acts by blocking voltage-gated potassium channels, prolonging action potentials and thereby increasing neurotransmitter release at the neuromuscular junction. The drug has been shown to reverse saxitoxin and tetrodotoxin toxicity in tissue and animal experiments. In calcium entry blocker overdose in humans, 4-aminopyridine can increase the cytosolic Ca2+
concentration very efficiently independent of the calcium channels. Multiple sclerosis
Fampridine has been shown to improve visual function and motor skills and relieve fatigue in patients with multiple sclerosis (MS). However, the effect of the drug is strongly established for walking capacity only.