Albuterol is a type of adrenergic bronchodilator prescribed for people with asthma, emphysema, bronchitis and other lung diseases, according to the Mayo Clinic. It works by relaxing and opening air passages to the lungs to make breathing easier, which can prevent and treat so-called bronchospasms — wheezing, coughing, shortness of breath and chest tightening.

However, people should treat it as a rescue inhaler, not as a daily drug, said Dr. Len Horovitz, a pulmonary specialist at Lenox Hill Hospital in New York City.

"It's what you reach for when you really need something," Horovitz told Live Science. "It's an 'I need it now' drug."

Inhaler and tablet dosage

Adults and kids over age 4 in need of albuterol to prevent or treat bronchospasms can take two puffs every four to six hours, Horovitz said. To prevent exercise-induced bronchospasm, the Mayo Clinic says adults and children over 4 can take two inhaler puffs about 15 to 30 minutes before exercise.

But "if you're using albuterol more than twice a week, there's something wrong with your regimen, and you need to consult a doctor," he said. 

Albuterol can be taken as a nebulized solution (a liquid that has been turned into an inhalable mist via a nebulizer machine) or as an aerosol that can be inhaled by mouth through an inhaler. 

Aerosol inhaler albuterol comes in canisters designed to provide about 200 inhalations. After using the exact number of inhalations, it is important to throw the canister away, even if it still contains some liquid and continues to spray. Once the listed number of puffs has been exceeded, the inhaler may not provide the correct amount of medicine. Some inhalers come with a counter that keeps track of the number of sprays used. When the number reaches 020, it is time to call the doctor for a refill. If there is no counter, patients must keep track of inhalations on their own.

The National Institutes for Health (NIH) has step-by-step instructions for using an inhaler and a nebulizer.

Patients taking albuterol through tablets, extended-release tablets or liquid should follow their doctor’s instructions exactly. It is important to swallow the extended-release tablet whole and not to chew, crush or break it. Part of the extended-release tablet may appear in patients’ stools while using the medicine. This is not a problem and no cause for concern.

Side effects

Albuterol may cause side effects. The NIH lists the following as less serious, though a doctor should be consulted if they don't go away:

• uncontrollable shaking of a part of the body
• nervousness
• headache
• nausea
• vomiting
• cough
• throat irritation
• muscle, bone, or back pain 

The following are more serious side effects and, if experienced, a doctor should be consulted immediately:

• fast, pounding, or irregular heartbeat
• chest pain
• rash
• hives
• itching
• swelling of the face, throat, tongue, lips, eyes, hands, feet, ankles, or lower legs
• increased difficulty breathing
• difficulty swallowing
• hoarseness

It is possible to overdose on albuterol. The following are symptoms of overdose:

• seizures
• chest pain
• fast, irregular or pounding heartbeat
• nervousness
• headache
• uncontrollable shaking of a part of the body
• dry mouth
• nausea
• dizziness
• excessive tiredness
• lack of energy
• difficulty falling asleep or staying asleep

Before taking albuterol, patients should tell their doctor if they suffer from any of the following symptoms:

• heart disease, congestive heart failure, heart rhythm disorder, or high blood pressure
• epilepsy or another seizure disorder
• diabetes
• overactive thyroid

Patients should tell their doctor if they are pregnant or are planning to become pregnant. However, "the most harmful thing to an embryo or fetus is lack of oxygen," and women should take albuterol if they need it and if their doctor approves, Horovitz said. Between 4 percent and 12 percent of pregnant women in the U.S. have asthma; and 3 percent of pregnant women take asthma medications, including bronchodilators like albuterol, according to the CDC.

A study published in the January 2012 issue of the journal Pediatrics showed that using asthma medicines during pregnancy — albuterol was the most common such medicine used in the study — didn't increase the risk for most birth defects studied. However, it showed that the medication might increase the risk for some birth defects, such as birth defects of the esophagus, anus and abdominal wall.

The FDA categorizes albuterol as a category C drug, meaning that it is unknown if it could harm a fetus. It's also unknown about its effects during breastfeeding, so women should proceed with caution before taking it, according to the Mayo Clinic.

By Jessie Szalay, Live Science