About ten million Americans suffer from asthma—attacks of breathlessness and wheezing caused by narrowing of the bronchioles, small airways in the lungs. The linings of the bronchioles become inflamed and swollen and fill with phlegm; a chronic cough may develop from attempts to free the obstruction. Asthma attacks kill more than 4,000 Americans each year. The disorder is caused by allergic reactions to pollen, dust, feathers, and animal hair, and also by cold air, infections, exercise, and air pollutants. Bronchodilators can be used to relax the bronchial muscles and widen the airway; synthetic steroids reduce inflammation and the resulting swelling. But beta-agonists (like Proventil), the drugs most commonly used as bronchodilators, may cause sleeplessness, jitteriness, and nausea; and steroids when used for more than a few months have more serious side effects, including bone loss, seizures, and bleeding.

Several studies have shown that THC acts as a bronchodilator in both normal subjects and patients with either chronic bronchial asthma or experimentally induced bronchial spasms. Since irritating effects of THC and tars in marijuana smoke have the potential to produce chronic bronchitis in heavy users, it may seem surprising that many people with asthma find smoked marijuana useful. Apparently the bronchodilator effects outweigh the irritation for some patients. Lisa is one:

I began developing inhalation allergies at age fourteen. An allergist diagnosed seasonal allergic rhinitis from ragweed pollen (i.e., hay fever) and prescribed antihistamines and decongestants for symptomatic relief.

A few years later, I began having mild asthma attacks (i.e., wheezing and tightness in chest) when exposed to cats. To give you an idea of how sensitive I was to cat dander, I once walked into a vacant apartment and announced that there must be a cat present. I was informed that there was no cat present – it had moved out with its owner two weeks earlier.

Since I only had asthma when exposed to cats, I managed my condition by simply avoiding cats. (Naturally, I fell in love with a guy who owned an adorable and affectionate kitten. When the relationship turned serious, I asked him to give the cat away. I knew he really loved me when he did. We’ve been married for almost eighteen years now.)

Since I had never been allergic to dogs, we adopted a dog. Within six months, I developed an allergy to dog dander, including asthma. I self-medicated with over-the-counter products, Primatene mist for immediate relief and Primatene tablets for longer-lasting relief.

Over time, I began experiencing asthma attacks even when I was not exposed to animals. I got it from strenuous physical activities, from breathing cold air, and when leaving airports (always when I smelled ozone). Eventually, just lying down in bed brought a feeling like suffocation.

So, at age thirty-one, I finally went back to an allergist, who tested my reaction to a variety of antigens. I showed a significant reaction to skin tests for ragweed pollen, grass pollen, tree pollen, cat dander, dog dander, dust mites (all 3 strains tested), and molds (all three strains).

At my allergist’s suggestion, I began a regimen of allergy shots, which I received every three to four weeks for about five years. He also prescribed an oral antihistamine/decongestant for my sneezing and stuffy nose, and an asthma inhalant, Proventil, to be used as needed. The shots reduced my reliance on antihistamines and decongestants, but did not reduce my need for asthma medication.

I have never had an asthma attack that was severe enough to send me to the emergency room, but I do get attacks of mild-to-moderate severity at least twice a day. For the past seven years, I have taken two "puffs" (the recommended dose) from my Proventil inhaler at the onset of wheezing or a feeling of constriction in my chest.

Usually, I get adequate relief at the recommended dosage within two or three minutes, but if not, I’ll take a third or even a fourth puff, depending on the severity of the remaining symptoms. While these higher doses often give me headaches or make my heart race, I prefer these side effects to the alternative feeling of having the breath squeezed out of me.

On rare occasions, higher doses will produce excessive bronchial dilation, which makes breathing just as uncomfortable as asthma does. Unfortunately, it is difficult to titrate the dose so as to take only as much drug as is needed. The metered-dose inhaler dispenses 50% of the recommended dose with each actuation, which means that my choices are 100%, 150%, or 200% of the recommended dose.

On occasion, I have also used another prescription inhalant, Serevent, which supposedly reduces the incidence of acute attacks. But I rarely use Serevent because it tastes terrible and I’m not convinced that using it substantially reduces acute attack frequency. Since Serevent cannot be used to treat acute attacks, I still need to use Proventil when these attacks occur.

The only legal drug I have ever taken that truly prevented asthma attacks was Medrol, a corticosteroid that was prescribed for non-asthma indications. Unfortunately, corticosteroids can have some very nasty side effects if taken for a long time, so it really isn’t suitable for chronic use as an asthma prophylactic.

I discovered that marijuana relieves (and even prevents) asthma quite by accident. For years, I thought my reaction was idiosyncratic. Then I read that some doctors were interested in performing clinical trials using marijuana to treat asthma, and I realized that other people must have experienced similar relief.

I find that smoked marijuana provides better relief of asthma than prescription drugs for four reasons.

(1) Marijuana seems to produce faster symptomatic relief than Proventil , and speed is important when you’re having trouble breathing.

(2) Marijuana seems to increase lung capacity and produce deeper breathing than Proventil. (In fact, marijuana seems to enable me to take deeper breaths than I can take even when I’m not having an asthma attack.) There are a number of objective tests of lung capacity that could be used to test this hypothesis.

(3) Since it take more "puffs" of marijuana to get relief than "puffs" of Proventil, it is easier to titrate the dosage of marijuana. I find this to be true even though the strength of marijuana (and therefore the necessary dose) varies widely due to genetic and environmental variation.

(4) Even when I smoke more marijuana than I need to for asthma relief, it does not make my heart race, give me headaches, or produce excessive bronchial dilation. It does tend to make me sleepy, which actually makes it perfect for right before I go to bed, when I consistently need to use Proventil to prevent the asthma attack that inevitably starts as soon as I lie down.