Tetracycline

What are tetracyclines?

Tetracyclines are oral antibiotics that are often used to treat skin conditions. There has been more than 50 years of experience with these drugs, which were originally derived from the soil. bacteria Streptomyces aureofaciens.

The original base drugs, chlortetracycline, tetracycline and oxytetracycline, have been replaced by products that are better and more absorbed. lipophilic, with excellent fabric distribution. These include:

• Doxycycline
• Lymecycline
• Minocycline
• Sarecycline

Doxycycline is the most commonly prescribed tetracycline.

Chemically modified tetracyclines are under development to reduce antibiotic activity and increase their anti-antibiotic activity.inflammatory effect.

What are tetracycline and its derivatives used for?

Tetracyclines are broad-spectrum antibiotics that are often used to treat infections of the skin, chest, urethra, and pelvis. Doxycycline is indicated for a wide range of infections including syphilis, Lyme disease, Q fever, The Rocky Mountains saw fever and plague. It is also widely used for malaria. prophylaxis.

Doxycycline is also effective in controlling inflammatory and non-infectious skin. mucous membrane diseases, including:

• Acne

• Rosacea

• Newspaper dermatitis

• Hidradenitis suppurativa

• Recurrent aphthous stomatitis
• Bullous pemphigoid
• Granulomatous disorders such as sarcoidosis
• Pyoderma gangrenous
• Sweet disease
• Pityriasis Lichenoides Chronica.

It is important to note that the use of tetracyclines does not increase Staphylococcus aureus resistance (see MRSA).

How do tetracyclines work?

As antibiotics, tetracyclines interfere with the protein synthesis of susceptible bacteria.

They are too anti-inflammatory agents

• They inhibit matrix metalloproteinases (MMP), hydrolases and phospholipase A2: these enzymes are active in dermal inflammatory skin disorders.
• They reduce the production of pro-inflammatories. cytokines such as TNF-a, IL-1B and IL-6.
• They are antioxidants, reducers free radicals production and nitric oxide.
• inhibit angiogenesis and granuloma training.

What is the usual dose?

The dose of doxycycline antibiotic is 100 mg once or twice a day. It should be taken in an upright position, with plenty of water.

Lower doses of doxycycline have been shown to be effective in rosacea (20 mg twice daily or 40 mg once daily). The lowest dose of doxycycline available in New Zealand is 50 mg. The effect of low-dose doxycycline on other skin disorders is unknown, and it is quite common for a dose of antibiotic to be prescribed.

A current The minocycline foam formulation was approved for use in acne by the US Food and Drug Administration in 2019.

How long are tetracyclines taken?

Infections are treated for 7 to 28 days, depending on the condition being treated.

Inflammatory disorders take several weeks or months to respond to tetracyclines, such as doxycycline. They are often prescribed for months or years for inflammatory skin disorders. They are not curative for these conditions.

There is a lag period of one to three weeks between the dose change and its effect on the skin. If the skin problem worsens, go back to the previous higher dose and continue with it or as directed by your doctor.

What are the side effects and risks of tetracycline and its derivatives?

Tetracyclines should not be taken by pregnant or lactating women, or by children under 12 years of age, as they discolor growing teeth and may cause enamel hypoplasia (malformed permanent teeth). Staining of permanent teeth is usually temporary but can persist for long periods. They can also affect the bones.

Doxycycline is generally very well tolerated, particularly at a subantibiotic dose. Allergy It can happen, but it's rare. There are some important precautions.

• It should be taken in an upright position and with plenty of water, to reduce esophagitis. Wait about an hour before going to bed
• Patients should protect the skin and nail from sun exposure, as it is photosensitizing and can cause unexpected sunburn
• May cause nausea, vomiting, and diarrhea; better tolerated when taken after a meal than on an empty stomach
• prone women vulvovaginal candida infection (candidiasis) with broad-spectrum antibiotics should consider prophylactic intermittent topical treatment systemic azole antifungal agent

Minocycline has a higher risk of serious adverse effects compared to doxycycline, so minocycline is best avoided as a first-line agent. These include:

• Drug hypersensitivity syndrome
• Autoimmune reactions
• dizziness and headache
• After a long time use, blue pigmentation skin and nails

Minocycline is less likely than doxycycline to cause photosensitivity.

Drug interactions

Important drug interactions of tetracycline and its derivatives include:

• Rise risk intracranial hypertension with systemic retinoids (acitretin, isotretinoin, alitretinoin)
• Decreased bioavailability of tetracyclines with iron, aluminum, magnesium, calcium, rifampin, celestipol, and anticonvulsants.
• Increased renal toxicity with diuretics
• May increase lithium concentrations, which can lead to toxicity.

Effect on contraceptives

There is little evidence that tetracyclines reduce the effectiveness of the oral contraceptive pill unless they cause gastrointestinal discomfort. However, to be absolutely safe, extra precautions must be taken, particularly in the first four weeks of starting antibiotics. Discuss this with your doctor.

If you develop side effects, let your doctor know. You may need to stop taking the tetracycline or change the brand.