Emodule from 8/14/12
How to decide which side effects are most important
Every drug has multiple side effects. In general you should identify no more than 3 significant side effects. A side effect is significant if:
1. It is caused very frequently by a drug. For example, the non-steroidal anti-inflammatory drugs (NSAIDS) all cause GI upset in a significant number of patients.
2. It is life-threatening. For example, the antihypertensive drug nitroprusside contains cyanide groups which can be released in vivo. It is unusual, or it causes any syndrome. For example, the antihypertensive drug minoxidil can cause hypertrichosis (hair growth). This unusual side effect, which is not desirable in some patients, may be used to advantage by others. (The hair-growth treatment Rogaine is simply minoxidil in ointment form).
3. Some unwanted effects of drugs are simply an extension of the desired effect. For example, the anticoagulants such as heparin or other "parin"s, warfarin, or the antiplatelet agents, all have excess bleeding as an unwanted side effect. Similarly, the antihypertensive drugs can cause hypotension, immunosuppressants increase the likelihood of infection, diuretics can cause dehydration or loss of specific ions, and any drug that has anticholinergic effects will cause the spectrum of effects that result from parasympathetic inhibition. Also, any drug that can get into the CNS can cause behavioral effects.
The possibility of liver damage has been demonstrated with almost all drugs, probably because the liver produces potentially toxic metabolites. In addition, there are anomalous liver reactions in some individuals, probably the result of an allergic response to any given drug. The problem is usually manifested by an increase in liver enzymes. However, the liver is an extremely robust organ, and most of the drugs that can elevate liver enzymes cause only transient problems. While drug-induced liver damage is the major cause of hepatic pathology, and any drug can cause an anomalous response, there are only a few that have been identified as significant hepatotoxins. These are listed below under hepatic toxicity.
There are three side effects commonly seen with most drugs: GI upset, rash, and headache. Unless any of these fits one of the 3 categories above, (for example, NSAIDs frequently cause GI upset), you can safely ignore these.
The following is a list of side effects (or unwanted effects) that I believe are "memorable". When combined with the rules for significance given above, they should cover almost all of the side effects you need to remember for any specific module.