Medication Side Effects

Why would you take a medication that might
cause "hot dog fingers"?

Not long ago a brokerage firm ran a TV advertisement which spoofed pharmaceutical ads. In it a man sits at his computer while the TV is on showing an ad for a new allergy drug. Soothing music plays in the background as a family picnics in a field of daisies free of their usual spring time allergies. Its all very nice until the disclaimer pops up on the screen warning of all the potential side effects including the possibility of developing some presumably horrible condition known as hot dog fingers. The viewer of course logs on to his brokerage account and sells all his shares in the drug company before the disclaimer has even finished scrolling by. This is all very good for the company you trade stocks with although maybe not so much for the one that makes the imaginary allergy medicine, but back in real life, no one is really going to weep for either company. Personally I don't really care who wins or loses the ad wars, except that these sorts of disclaimers and side effect lists are not particularly good for patients either.

All medications have some risk of side effects. Over the last 20 years there have been efforts to make the public more aware of the potential side effects of the drugs they use. Doctors may discuss side effects with their patients. Pharmacies now give print outs of side effects with every prescription filled. When all else fails the internet is awash in sites that provide an official list of side effects and forums where people will offer up their own unofficial list of complaints they've attributed to whatever drug we are interested in.

One would think that this encyclopedia of information would make for a more educated consumer better equipped to make confusing medical decisions, but that may not always be the case. Much of the information regarding medication side effects is based on very weak evidence and even that which is correct is rarely placed in proper context. These sorts of inaccuracies and lack of perspective often leads patients to misperceptions that can discourage them from taking medications which may be critical to their health.

When we look over a list of possible side effects from the pharmacy or on the internet we assume that these lists are well researched. Some of the information in that list is indeed based on well controlled studies in which the side effect was found to be more common among patients taking the drug than it was in those who were on placebo, but among the endless list of side effects only a handful are usually well researched. The vast majority of the side effects on the list are based on questionable anecdotal reports. In other words if someone taking drug A develops a headache and decides to file an adverse reaction report, headaches may now be listed as a potential side effect. In such cases the symptom may have been due to the drug or may have been completely unrelated, but there is no way to know. In fact headache is listed as a side effect of almost every common drug. It is very unlikely that all drugs cause headaches. Its much more likely that headaches are very common occurrences and that sooner or later people get headaches on every drug just because people get headaches anyway.
In a similar vein many drugs are blamed for symptoms that are not really side effects of the drug but side effects of the condition they are used to treat. For example, the side effects list for the allergy medication Claritin includes; "bronchitis, bronchospasm, coughing, laryngitis, and sneezing". These are all conditions for which a person rightly or wrongly might have taken Claritin in the first place. Yet you would expect patients to have these symptoms not because the drug caused them, but because that is why they took the drug.

While some side effects are very likely not due to the drug at all, others are accurately attributed to a drug but not put in proper context, or for that matter any context. For a patient to properly decide whether a drug is worth taking they need to know what the risk of a particular side effect is and whether that risk applies to them at all. Most side effect lists don't give patients any idea of the actual risk or whether certain predisposing conditions or circumstances are required for those side effects to occur. It makes a big difference if a particular side effect occurs one in a hundred times or one time in 10 million or perhaps only in people who wear orange sneakers.
Fosamax is a drug which is commonly prescribed for osteoporosis. One of the side effects that has gotten a lot of press coverage is the risk of a condition known as osteonecrosis of the jaw which is a breakdown in the bone of the jaw. What the lists rarely tell patients is that the risk is approximately 1 in 100,000 and that 85% of these cases have occurred in patients with a history of breast cancer or multiple myeloma. For the average individual the risk of this side effect is extremely rare.

Oddly the side effect list does not even take into account the manner in which a drug is used. The list of side effects for cortisone is virtually the same whether the drug is used intravenously, as a pill, as a nasal spray or applied to the skin as a cream even. The effects of a drug on the body will vary dramatically though depending on how it is used. Side effects more common to a drug when used orally for example may occur rarely or never when applied topically.

Sometimes the particular side effect for a drug occurs only when the drug is improperly used yet the information given to patients does not reflect this. A good example here is the medication Synthroid which is used to replace diminished levels of thyroid hormone in patients with hypothyroidism. Synthroid is essentially the same hormone your own thyroid makes. When the thyroid is not able to make enough to meet the body's needs doctors often treat this condition by supplementing the body's own thyroid hormone with the pill form. This generally should not cause any side effects since all we are doing is adding back something that should already be there in the first place, and yet the list of side effects is long.
The list includes things such as "hair loss, flushing, decreased bone mineral density, menstrual irregularities, impaired fertility, diarrhea, palpitations, irregular heartbeat, increased pulse, nervousness, anxiety, insomnia, and heat intolerance". All of course are symptoms of too much thyroid hormone. They are not side effects one should expect of this drug when used properly and in the correct dose. Unfortunately patients reading this may assume that the medication might cause these symptoms even when properly prescribed. Sometimes it frightens them enough that they fail to take their medication which can lead to more serious problems.

Of course medication side effects are a real phenomena and its important for people to be aware of them but bad information can be more dangerous than no information at all, especially if it causes a patient to stop taking essential medications. Its important for patients to understand these shortcomings when they read about potential side effects for their medications. 

So how do you determine what side effects are important and which ones are not?   Unfortunately its not as easy as it should be, but its not impossible.  Your physician is always a good resource. Your doctor uses these drugs all the time. They know what sort of complaints turn up frequently and which ones almost never do. It's impossible to review the entire list of side effects with a patient in the limited amount of time available during an office visit so I like to go over two types of side effects, the most common ones ( most of which are minor) and the most serious ones ( most of which are very rare).

You can also look up something called the “package insert” or "prescribing information" for the drug. These can be found in the Physicians Desk Reference(PDR) or on the internet by typing the name of the drug and then "prescribing information" into your favorite search engine. For example "Lipitor Prescribing Information" will bring up the official Lipitor site with a link for the Physicians Prescribing Information. This document is required by the FDA for all prescription medications. In that document will be a list of all “side effects”.  As we discussed already, this list is  flawed for the all reasons described above but there will also be a table of side effects comparing the drug to placebo. In that table you can see a short list of side effects that were studied. It will show how often the side effect occurred with the drug and how often it occurred with placebo.  If for example 1% of patients on the drug got "hot dog fingers" and 0.9% of patients on placebo developed that condition then it's probably not a real side effect but if 3% of patients on the drug had hot dog fingers compared to only 0.9% on placebo then you may want to keep some mustard handy.

Deciphering this sort of information can be confusing even to those who do this for a living so keep in mind a few last thoughts. Doctors usually have gone through the risk vs benefit analysis for you already before they prescribed your medication. Yes every drug has potential side effects but the majority of people who take those drugs will never have any of those side effects. On the other hand the condition for which they are treating you has real side effects and left untreated they could in some cases be life threatening. This is the calculation we make each and every time we give a patient a new medication. Are the potential benefits greater than the potential side effects? Of course you may still have questions. Maybe your doctor was busy and didn't have time to consider everything. Maybe there is something about your medical condition or other medications they were not aware of. Those are all good thoughts and if you are unsure or have concerns about side effects you should discuss them with your doctor, but never make decisions about your medication on your own based on these concerns or because of something you saw online or in literature you received from the pharmacy. Always discuss any questions or concerns with your doctor first  before making a decision about stopping or starting a medication.

Michael Melgar, MD

Putting this in perspective

What would happen if we were to apply the same guidelines we use for drugs to
It might look something like this.

Side effects of bottled water may include:

  • Hair loss, divorce, headache, fatigue, tax audit, and sunny days - incidental occurrences that had nothing to do with drinking water but may have occurred some time after you drank it
  • Thirst, dirty skin, oily hair, brown lawns - We use water to treat these things. Water doesn't cause them
  • Increased urination, burning nostrils, and ruined hair and clothes. - This really depends on whether you are drinking it, snorting it, or having the product poured on you at a fancy event.
  • Wrinkled skin and sudden death - Very real side effects but you have to float in it all day or drink a hundred bottles in an afternoon. Dose is important. 
  • Short circuiting, stiff joints, and whole-body melting - Of course these only apply if you're a robot, the tin man, or the wicked witch of the west