Inner Nature: The medicine/poison cabinet

By Vidya Rajan, Columnist, The Times

We seldom think of the home or medicine cabinet as a storehouse of poisons, but that is what they are. From the very food we eat, the sprays we clean with, to the drugs we take, the chemical activity of – um, chemicals – can have diabolical effects upon biological systems. In this article, I will explore a few of the drugs we use to keep ourselves healthy, and how drugs can become poisons.

That drugs can be dangerous is the reason why so many are regulated, and available only by prescription by a licensed physician or psychiatrist. Most drugs are derived from other living organisms which use the chemicals to ward off predators, and they do this by messing with the biochemistry of the attacker, sometimes lethally. However, some drugs are from inanimate sources. Elements such as lithium, iron, potassium, iodine, zinc, and sodium, and compounds such as bicarbonate of soda and calcium carbonate, are used as part of the spectrum of pharmacological interventions to manage health. But the questions arise: What distinguishes a poison from a drug? Is the difference due merely to a dosage effect? What interactions can drugs have with each other that singly they are okay, but together will send you six feet under? Why are there so many potential side effects for each drug?

Drugs act through a physiological intermediary, through which they activate or shut down a pathway. Dosage matters here to modulate the pathway correctly. Consider a problem of acid overproduction in the stomach. There are two ways to manage this problem: 1. turning down acid production levels or, 2. absorbing the excess; both will have the desired outcome of less acid. But other problems may arise from the reduction of acid levels. If most or all the acid is absorbed, there may not be enough left to digest protein, or potential pathogens or their eggs, and will have the undesired side-effects of malnutrition or parasitic infestation. But if not enough absorption of acid occurs, the remaining acid may cause other problems such as possible ulceration, reflux, or heartburn. Therefore, the dose must be achieved that sponges up just the right amount of acid – not too little, and not too much.

A second consideration for drugs is their interactions with other drugs or the body itself, if it changes the drug’s persistence or activity. As a simple example, a drug that requires acid in the stomach to be activated, such as a supplementary digestive enzyme, will be modulated by the levels of acid. Agonistic, or similar actions, will be amplified. For example, barbiturates and alcohol are both nerve depressants and, taken together, can be lethal. So also aspirin and warfarin, both of which act to thin blood, will have lethal additive effects. Antagonistic drugs, such as morphine and naloxone, have opposite effects at the same receptor. Thus, a morphine overdose can be reversed by administering naloxone. Drugs whose actions involve the brain are particularly complicated in this respect – their outcomes are affected regionally by agonistic and antagonistic effects, but they can even have systemic effects because of their regulation of the secretion of neurotransmitters and hormones.

Drug action is further modulated by whether the drug is rapidly or slowly broken down, and the organs involved in its removal from the body. Drugs metabolized through biochemical pathways in the liver or the kidney can place excess stress on those organs if used in conjunction with other drugs metabolized via the same organ. For example alcohol and acetaminophen – a popular analgesic – are both metabolized in the liver using similar oxidative enzymes. Taking them together may place such a large load on the liver that it can cause liver failure and death. Some foods may interfere with drug metabolism as well. Grapefruit juice is known to interfere with some liver enzymes that break down drugs like cholesterol-lowering statins, leading to a drug buildup which can then lead to muscle pain or damage. Over-the-counter non-steroidal anti-inflammatory drugs (NSAIDs) can affect kidney function, impeding the removal of drugs from the body. So be sure to list these in your medication lists when you see your physician for your annual checkup! Illegal or street drugs can also interact with prescription drugs in the body. The list is long! Here is a place where you can check prescription drug interactions: Stay safe by checking with your doctor, especially if you are required to take multiple medications. Keep your medications away from children. Expired and no-longer-needed medications can be disposed at the Police Station and through Controlled Substance Public Disposal Locations (search for your closest location at Controlled Substance Public Disposal Locations – Search Utility (

It is not usual practice to praise federal governmental institutions, but the Food and Drug Administration has been the bulwark against ineffective treatments marketed as panaceas, and against food and drug adulteration in the United States. The first part of its mission statement reads as follows: “The Food and Drug Administration is responsible for protecting the public health by ensuring the safety, efficacy, and security of human and veterinary drugs, biological products, and medical devices; and by ensuring the safety of our nation’s food supply, cosmetics, and products that emit radiation.” The FDA requires data on two key requirements prior to licensing a drug: safety and efficacy. These data are gathered through clinical trials (at levels I, II, and III, as you may know from the testing of the vaccine against SARS-CoV-2, which causes COVID-19), and bolstered by the Vaccine Adverse Effects Reporting System (VAERS) where side effects of vaccines are reported to the FDA for safety follow up. But the FDA also demands that any negative drug interactions that are found are publicized by the drug company – this is the reason for drug labeling and the laundry list of side-effects that accompany any over-the-counter or prescribed drug. The FDA is so trusted that many other countries have adopted the practices they pioneered, such as Good Laboratory Practice (GLP) and Good Manufacturing Practice (GMP) with stringent record-keeping and trackable supply chains.

To stay safe, read the small print, and be honest with your physician when they ask you which other drugs you take.

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