Tetracyclines
Doxycycline, Tetracycline, Minocycline (PO & IV)
- Broad spectrum with some Staph & MRSA, Some Gram- & Atypicals
- Used to treat unusual pathogens: Rickettsia, Lyme Disease, Tularemia, Vibrio, Brucella, Q Fever, Anthrax, Rocky Mountain Fever, Acne, Chlamydial infection, Mycoplasma infection, STD’s
- Doxycycline is the Tetracycline preferred choice due to the convenient BID dosing & lack of food-drug interactions
- Doxycycline & Minocycline can be used in patients with renal failure (because it is excreted in bile)
- Don’t give with products that contain- Ca, Mg, Zn, Fe, & Milk- It will decrease the effectiveness
- Side Effects: Hepatotoxicity (Liver failure), Photosensitivity, Falconi-like Syndrome (damage to kidneys from taking outdated/degraded Tetracycline), Intracranial HTN with severe headache & blurred vision, decreases effectiveness of oral contraceptives, Discoloration of teeth and decrease bone growth in children
- Contraindicated in children and pregnant/nursing women
- Renally impaired patients should not use tetracyclines, except doxycycline
Lyme Disease
- Caused by Borrelia burgdorferi
- infection results in skin lesions, headache, and fever, followed by meningoencephalitis and eventually arthritis
- A single 200mg dose of doxycycline given within 72 hours after a tick bite can prevent development of the disease
Mycoplasma Pneumoniae
- A common cause of community acquired pneumonia in young adults & people who live in close confines
- Treatment with doxycycline leads to shorter duration of fever, cough, and malaise
- Treatment with macrocodes is also effective
Cholera
- caused by Vibrio cholera
- Ingested in fecally contaminated food or water
- The organism multiplies in the GI tract where it recreates an enterotoxin that causes diarrhea
- Treatment includes fluid replacement & doxycycline which reduces the number of intestinal vibrios
Chlamydial Infections
- Chlamydia trachomatis is the major cause of sexually transmitted disease in the United States
- It causes nongonococcal urethritis, pelvic inflammatory disease, & lymphogranuloma venereum
- Doxycycline or azithromycin is used to treat chlamydial infections
Rocky Mountain Spotted Fever
- caused by Rickettsia rickettsii
- Characterized by fever, chills, and aches in bones and joints
- Response to tetracyclines is prompt if the drug is started early in the disease process
Side Effects
- Hepatotoxicity (Liver failure)
- Photosensitivity
- Falconi-like Syndrome (damage to kidneys from taking outdated/degraded Tetracycline)
- Intracranial HTN with severe headache & blurred vision
- ↓ effectiveness of oral contraceptives
- Discoloration of teeth and decrease bone growth in children
Key Notes
The use of Tetracycline is contraindicated in children younger than age 8 because of permanent staining of the teeth
Doxycycline can be administered safely with milk or an antacid, but the other Tetracyclines cannot
If a patient is taking Minocycline, a sudden change in mental status may indicate intracranial hypertension