Medicine & Drug Toxicities

All drugs have side effects. This is a well known and respected fact in medicine. In many cases these side effects only occur in high doses, but in some cases these side effects will occur at the prescribed dose, but only to very minor degrees. Even commonly available drugs such as aspirin and paracetamol have side effects, so you should always read the packed before deciding to use any of them.

Many drugs will be described as having a 'something' toxicity. The purpose of this article is to explain some of the more common ones and what they actually mean to your body.

Neurotoxic: Affecting nerves. This sounds quite bad, but often the drug is having an affect on the support cells that surround the neuron rather than the neuron itself. Neurotoxicity may be noticed in a variety of ways. You may feel a numbness, tingling, pain or experience unintended tremors or twitches.

Nephrotoxic: These drugs have side effects on your kidneys. Kidneys are relatively sensitive to drugs, as many metabolites pass through them to be excreted in urine. Drugs that normally have no effect on the kidneys may become nephrotoxic if you become dehydrated. Drugs can endanger the kidneys by reducing their blood flow or by affecting the individual cells in the kidney directly.

Ototoxic: Drugs which are ototoxic affect the ear, or the vestibulocochlear nerve which innervates it. Toxicity may affect your balance or your hearing. For example, you might notice a constant ringing noise.

Hepatotoxic: Drugs with hepatotoxicity are quite common, because many drugs are metabolised to some extent by the liver. The liver is a very tough organ and will still perform adequately with less than half of its mass, and has a great ability to regenerate, but toxicity can still occur. The liver has many functions, including the production of enzymes, production of bile, production of coagulation factors for blood blotting, maintaining protein concentration in the body, and many different metabolic pathways. If hepatotoxicity is occurring, there are a variety of things you may notice. Jaundice (a yellow colouring of your body) is an extreme example. There may also be difficulty digesting fats, vitamin deficiencies, reduced blood clotting, oedema or other subtle signs.

Myelotoxic: These are drugs with an effect on your bone marrow. Sometimes this is desired if you have an autoimmune disease, but often it's not. These drugs reduce the production of one or all types of cells produced by the bone marrow- red blood cells, white blood cells and the precursors of platelets. Symptoms will depend on what has been affected, but may include a vulnerability to illness, anaemia or reduced clotting.

Cardiotoxic: Drugs that damage the heart are less common. They usually produce subtle signs of reduced activity, increased fatigue, less ability to exercise etc.

If you are on medication and experience any of these signs, you should mention them to your doctor before seeking more medicine to treat these symptoms. A change of medication, or a different dose, may be required. Always ask your doctor.