Drug Excipients, Let People Rejoice, Let People Worry

Drugs, are substances used to prevent, treat and diagnose diseases. Theoretically, all chemical substances that can affect the organs, physiological functions and cellular metabolic activities of the body belong to the category of drugs.

The composition of drugs, except for a small part of the active ingredients with pharmacological effects, most of them are excipients, that is, excipients and additives used in the production of drugs and prescriptions, in addition to the active ingredients, have been evaluated in terms of safety and included in the drug formulation.

In addition to excipients, acting as carriers and improving stability, pharmaceutical excipients also have important functions such as solubilization, solubilization aid, slow release and controlled release, which are important components that may affect the quality, safety and efficacy of drugs.

In fact, excipients are generally inactive ingredients that neither affect the pharmacological effect of the drug, nor interact with other components of the drug or packaging materials.

Therefore, in case of clinical adverse reactions, the presence of excipients is often overlooked when the main drug component is the first thing that comes to mind. However, recent studies have shown that almost all drugs contain ingredients that can trigger allergic or stress reactions in some patients, so excipients may also cause adverse reactions.

Adverse reactions caused by the addition of excipients to drugs are related to the nature of the excipients themselves. Some excipients have certain toxicity, once the concentration is too high, or long-term use, it is possible to cause adverse reactions.

For example, if propylene glycol is used as an excipient to dissolve preparations of insoluble drugs, propylene glycol will be converted into lactic acid by acetaldehyde dehydrogenase when administered in large doses, which may lead to lactic acidosis, hemolysis and other adverse reactions, and long-term high-dose infusion may also cause some damage to the kidneys.

In addition, the preparation process, ethanol is used as a solvent for a variety of insoluble drugs; however, in the process of medication, there may be a burning sensation and pain induced by ethanol, and if the site of use is close to nerve tissue, it may also cause nerve damage.

For example, a children's hospital in Jiangxi used "three volt paste", in order to improve the efficacy, but the young ginger in the auxiliary materials replaced with old ginger and the concentration of ethanol, resulting in some children with skin itching, burns, blisters and other adverse reactions.

In addition, the use of cephalosporin antibacterial drugs, if combined with drugs containing ethanol as an excipient, there is a risk of "disulfiram-like" toxic reactions, symptoms such as flushing, headache, nausea, vomiting, decreased blood pressure, and even shock.

Therefore, strictly speaking, the combination of cephalosporin and compound licorice combination (whose solvents are ethanol) is not recommended for upper respiratory tract infections (colds), especially for elderly patients, to avoid serious adverse reactions.

　　Preservatives are also excipients that need to be added to many liquid preparations (e.g. eye drops, nasal drops) to stop the growth of microorganisms and to ensure the stability of the preparation.

However, long-term use of these preservative-containing eye drops can cause pathological damage to the eye surface; long-term use of preservative-containing nasal drops can cause damage to the cilia tissue of the nasal cavity, thus reducing the ability of the respiratory system to remove bacteria and dust particles.

Therefore, the long-term use of liquid preparations containing preservatives is not recommended, especially some of the current "Netflix" imported eye drops, etc.

The adverse reactions caused by excipients are also related to the patient's constitution.

In fact, for most patients, a little excipients do not have any effect, but because of individual differences, a very small number of patients may cause allergies or other adverse reactions to small amounts of excipients.

For example, lactose is a diluent for many tablets and capsules, but for patients who are lactose intolerant, it may cause diarrhea, abdominal pain and other adverse reactions after taking it. Lemon yellow is a coloring agent, but there is cross-allergenicity with aspirin, and individual patients may experience acute bronchospasm, urticaria, or even angioneurotic edema or anaphylaxis in severe cases.

In fact, once an adverse drug reaction occurs, it is difficult to distinguish whether it is caused by the active ingredient in the drug or the excipient, but it is necessary to prevent it before it happens, especially in special populations (elderly, children, pregnant and lactating women) when the drug is used for a long time and in high doses.

In addition, patients should understand as much as possible the precautions and contraindications in the drug instructions and inform their doctors and pharmacists of their past allergies and family history to ensure the safety of the medication.