Chlortetracycline is an active substance used as an antibiotic in humans and animals. It helps in infectious eye diseases and wound diseases of the skin. Through its use in agriculture, it can enter the food chain through the consumption of grain.
What is chlortetracycline?
Chlortetracycline is an active substance used as an antibiotic in humans and animals. It helps treat infectious eye diseases and wound diseases of the skin. Chlortetracycline (molecular formula: C22H23ClN2O8) is a crystalline solid substance, which is yellow, odorless and poorly soluble in water. The antibiotic belongs to the group of tetracyclines. In Germany, the drug is sold as chlortetracycline hydrochloride under the trade names Aureomycin, Aureomycin Eye Ointment (human medicine) and Animedazon Spray, Citrolan CTC, Cyclo Spray (veterinary medicine) and in Austria as Aureocort. The antibiotic was discovered in 1945 by the US botanist Benjamin Duggar. In 1948, the active ingredient was isolated for the first time from the bacterium Streptomyces aureofaciens. The bacterium, which has antibiotic activity, is found in upper soil layers and is highly effective against staphylococci, streptococci and certain bacilli in particular. Because of its yellowish coloration, the scientist named the drug aureomycin. Although the suffix -mycin rather suggests a fungus, it is actually a bacterium. However, this is capable of forming fungal tangles (mycelium). In veterinary medicine, the drug is mostly used as hydrochloride and in other dosage forms (spray, etc.) and is used to treat respiratory, urinary and gastrointestinal infections in various animal species. To check for possible resistance to it, an antibiogram is usually made beforehand. Chlortetracycline used in industrial agriculture can enter the soil through liquid manure, where it is absorbed by the roots of cereal plants.
Pharmacological effect
Chlortetracycline is similar to doxycycline in terms of its spectrum of activity. It ensures that the infecting bacteria can no longer form proteins and thus grow. This inhibits the maturation and spread of the pathogens. The substance is effective against staphylococci, streptococci, chlamydia, pneumococci, Escherichia coli and Haemophilus influenzae. It can also be applied preventively against wound infections. In humans, it is applied externally only; in animals, it is also applied orally (not in horses and ruminants). Chlortetracycline is only 30% bioavailable in human applications and is effective for 5 to 5 1/2 hours. It binds 50 to 55% to plasma proteins and about 75% is metabolized in the liver. It is excreted through the urinary tract and intestine (bile).
Medical use and application
When applied as an eye ointment, it is used to treat conjunctivitis (inflammation of the conjunctiva), eye skin irritation, eyelid margin inflammation (blepharitis), corneal inflammation (keratitis), and trachoma (a chlamydial infection of the cornea that can lead to blindness if not treated in time). In addition, chlortetracycline is used for skin infections caused by suppurated wounds, burns and abrasions. Thus, it helps with inflamed sebaceous glands and sweat glands (boils, abscesses), erysipelas, impetigo, and infections of the nail bed. Ulcus cruris (“open leg“), a lower leg ulcer that mainly affects patients with diabetes, and decubitus ulcers can also be combated extremely effectively with it. They often develop in bedridden patients at skin sites that have been exposed to pressure for too long. This happens, for example, if the affected person is not repositioned often enough. The capillaries of the skin are then compressed, so that the skin no longer receives sufficient oxygen and nutrients. If the resulting ulcer is not treated in time, it even affects tissues and muscles far below, leading to necrosis (dead tissue). For the duration of the application as an eye ointment, the patient should not use contact lenses under any circumstances. If the patient has forgotten to apply the ointment to the conjunctival sac, he or she should never apply twice the amount. Excess ointment can simply be wiped off with a clean paper towel. The eye ointment is applied to the conjunctival sac in a 0.5 to 1 cm strand at least every 2 hours. Mild eye infections are usually healed after 2 days.Nevertheless, the patient should continue the treatment for another 3 days. In more severe cases, additional oral administration of antibiotics may be required. After applying the eye ointment, the user may have blurred vision for a few minutes.
Risks and side effects
Allergic skin reactions (contact dermatitis, skin redness, [[rash|skin rashes||, increased photosensitivity of the skin, itching) and allergic mucosal reactions may occur with the use of chlortetracycline agents. If the patient develops photodermatosis when exposing their skin to UV light, they should stop treatment immediately and contact their doctor. In children under 8 years of age, the drug may in rare cases cause delayed bone development, underdeveloped tooth enamel, and permanent tooth discoloration. In addition, long-term therapy with chlortetracycline, as with other antibiotics, may cause the patient to become infected with other bacteria and fungi and develop resistance to strains of bacteria against which the drug is ineffective. Chlortetracycline should not be applied if the person suffers from hypersensitivity to the active substance or other tetracyclines, in the presence of ocular tuberculosis, fungal infections of the field of application hepatic and renal insufficiency, lupus erythematosus and in the case of pathogen change. Pregnant and breastfeeding women should also avoid the drug, as it can cause liver damage in the expectant mother and growth disorders in the unborn child. It also passes into breast milk. Women taking the contraceptive pill must expect a reduction in the effectiveness of the contraceptive. It may also interact with other medications.
