Over-the-counter (OTC) drugs are sold in pharmacies and other stores without a doctor’s prescription. There are dozens of OTC drugs in the market for common cold symptoms, such as runny nose, congestion, sore throat, headache, cough, fever etc. But just because they are easy to get, doesn’t mean that they always work, or that they are safe. Whether it is a prescription or OTC drug, dispensing medicine properly is important. Given incorrectly, drugs may be ineffective or harmful.

Categories of commonly used OTC medications
Pain relievers: The OTC products that relieve your headache, fever, or muscle aches are not all the same. That is because the pain relievers you see in the aisles of your local drug store or pharmacy are either nonsteroidal anti-inflammatory drugs (called NSAIDs), which include aspirin, ibuprofen, naproxen and ketoprofen, or acetaminophen. Each of these drugs has a different way of working. Aspirin and non steroidal anti-inflammatory drugs relieve pain by stopping the production of prostaglandins, which are natural chemicals in the body. Prostaglandins irritate nerve endings, triggering the sensation of pain. Commonly used non steroidal anti-inflammatory drugs include:aspirin, ibuprofen, naproxen and ketoprofen.

Antihistamines: Antihistamines work by blocking the receptors that trigger itching, nasal irritation, sneezing, and mucus production. The three types of antihistamines are:diphenhydramine, brompheniramine and chlorpheniramine.

Decongestants: Decongestants work by narrowing blood vessels in the lining of the nose. As a result, less blood is able to flow through the nasal area, and swollen tissue inside the nose shrinks. Pseudoephedrine is the only decongestant used as an OTC product.

Cough medicines: Cough medicines are grouped into two types: antitussives and expectorants. Antitussives, or cough suppressants, block the cough reflex. Dextromethorphan is a commonly employed antitussive. Expectorants, on the other hand, are thought to thin mucus and make coughing more productive in clearing the mucus from the airway. Guaifenesin is the only expectorant used as OTC products.

How to read an OTC drug label
You don't need a prescription to buy OTC medicine. But like prescription drugs, OTC medicines can also cause unwanted and sometimes dangerous side effects. Before you buy an OTC medicine, it is important to read and thoroughly understand the information on the drug label. Use the following as a guide. If you have questions about a medicine, ask your pharmacist or family doctor.

Active ingredient
The active ingredient is the chemical compound in the medicine that works to relieve your symptoms. It is always the first item on the label. There may be more than one active ingredient in a product. The label will clearly show this.

Uses
This section lists the symptoms the medicine is meant to treat. The US Food & Drug Administration must approve these uses. The uses are sometimes referred to as indications.

Warnings
This safety information will tell you what other medicines, foods, or situations (such as driving) to avoid while taking this medicine.

Directions
Information about how much medicine you should take and how often you should take it will be listed here.

Other information
Any other important information related to storage conditions etc.

Inactive ingredients
An inactive ingredient is a chemical compound in the medicine that is not meant to treat a symptom. Inactive ingredients can include preservatives, binding agents, and food colouring. This section is especially important for people who know they have allergies to food colouring or other chemicals.

Side effects of OTC medicines in adults
While OTC medicines have a low risk of side effects when used occasionally by healthy adults, they can pose risks for very young children, the elderly, pregnant and breast feeding women, people with kidney problems, and people taking more than one medicine. These people have an increased risk of side effects when they take OTC medicines.

Certain groups need attention for OTC medications
Children: It is necessary to understand that children are not ‘miniature adults’; the adult doses, scaled down based on body weights may not be safe or effective in the paediatric population. As neonates develop into infants and young adolescents, a number of physiological changes occur in their body composition e.g. change in body water, body fat, plasma proteins, and hormonal composition that influence drug disposition and dosage requirements. Certain intrinsic factors such as gender, race, heredity and inherited diseases and extrinsic factors such as acquired diseases, diet, and prior exposure to drug therapy may change drug disposition in the paediatric patients. In order to provide safe and effective drug therapy to such category of patients, it is important to gain knowledge of the pharmacokinetic and pharmacodynamic properties of each drug and the effect of development on its disposition.

How to give medicine to children
The most important thing for parents is to know what the drug is, how to use it, and what reactions to look for. A parent should ask the doctor or pharmacist a number of questions before accepting any prescription: What is the drug and what is it for?  Will there be a problem with other drugs my child is taking?  How often and for how long does my child need to take it?  What if my child misses a dose?  What side effects does it have and how soon will it start working?

Pregnant and breast feeding women
Drugs are likely to be self administered or prescribed by the physician during pregnancy. For various reasons, studies on the proper use of drugs during human pregnancy are few, and drugs describing during pregnancy is arbitrary rather than rational. Doctors have focused on identifying prescription drugs that pose risks for pregnant women ever since the 1960s, when thousands of children were born with devastating birth defects after their mothers took thalidomide for morning sickness. On the other hand, there has been an increased tendency of using non prescription drugs (NPDs) by the pregnant women. There is an utmost requirement to provide right drug information to such users of OTC medications, so that they may be well aware about the merits and demerits of OTC medications.

NPDs could pose risk in pregnancy:
Woman frequently assume that, if medications do not require a prescription by the physician they are safe to take during pregnancy, but most medicines have been tested only for use in the general adult population and not particularly during pregnancy. Although most of OTC medications contain warning advising pregnant women to consult a doctor before using them, many women due to what so ever reason do not do so. Studies suggest that women who use pseudoephedrine in their first trimester may have a higher risk of having a body born with gastroschisis. Studies revealed that aspirin has also posed increased risk of gastroschisis in a number of pregnant women. Ibuprofen and other nonsteroidal anti-inflammatory drugs like acetaminophen have been linked to the premature closure of the fetal ducts when used in 3rd trimester.

Pregnancy
Acetaminophen is generally considered safe for short-term pain relief during pregnancy.
It is very important to avoid use of  aspirin during pregnancy. It can cause abnormalities in the baby or problems during delivery. Avoid using other nonsteroidal anti-inflammatory drugs, especially during the third trimester of pregnancy. They can cause heart abnormalities in the baby.

Breast feeding
Acetaminophen and nonsteroidal anti-inflammatory drugs, such as ibuprofen provide safe pain relief for women who are breast feeding. Avoid using aspirin because it is excreted in breast milk and can cause rashes and bleeding problems in nursing infants. Limit long-term use of antihistamines. Antihistamines are excreted in breast milk, and may cause side effects such as sedation, irritability, crying, and sleep disturbances in nursing infants. Antihistamines may also interfere with the production of milk.

Older adults
The elderly use a number of medications at the same time and therefore need to pay careful attention to drug-drug interactions between OTC medications and prescription medications. Older adults talk with their doctor about the medications they take and potential interactions with OTC medicines.

There is a relatively high risk of kidney disease and GI bleeding in elderly patients who use nonsteroidal anti-inflammatory drugs.  Pseudoephedrine can increase blood pressure and the pressure in your eye that can lead to glaucoma. It can also make existing blockages in the urinary tract worse. Pseudoephedrine interacts negatively with many other drugs such as beta-blockers, antidepressants, insulin, and some medications that treat low blood sugar.

If you use a monoamine oxidase inhibitor (MAOI), a type of prescription antidepressant, or take any medication for a seizure disorder, you should avoid using pseudoephedrine. Pseudoephedrine can change the way these drugs work in your system. Some common monoamine oxidase inhibitors include: isocarboxazid, phenelzine sulfate and  tranylcypromine sulphate.

If you use an MAOI, you should not use dextromethorphan. Dextromethorphan interferes with the way monoamine oxidase inhibitors work.

Conclusion
The concept of over-the-counter medications is spreading its wings rapidly, which will generally benefit the rural class of people, as availability of such medications in general stores is expected to bring down the cost of medicines. An individual should take a rational decision when they have to make a choice between prescription drugs and non prescription drugs. Drugs in both categories are not devoid of adverse effects. When it comes to special cases like children, pregnant and breast feeding women, elderly patients etc. certain factors like ease and comfort to take medicines, availability of medicines, cost and traditional beliefs greatly influence their choice to take medicines. Due to obvious reasons, OTC medications have got an edge over prescription drugs. The need of the hour is to make a person aware and updated about the pros and cons of using OTC medications.