Susceptibility Testing of Bacteria Excluding Mycobacteria
The in vitro potency of Tromix is markedly affected by the pH of the microbiological growth medium during incubation. Incubation in a 10% CO2 atmosphere will result in lowering of media pH (7.2 to 6.6) within 18 hr and in an apparent reduction of the in vitro potency of Tromix. Thus, the initial pH of the growth medium should be 7.2-7.4, and the CO2 content of the incubation atmosphere should be as low as practical.
Tromix can be solubilized for in vitro susceptibility testing by dissolving in a minimum amount of 95% ethanol and diluting to working concentration with water.
Prolonged cardiac repolarization and QT interval, imparting a risk of developing cardiac arrhythmia and torsades de pointes, have been seen with treatment with macrolides, including Tromix. Cases of torsades de pointes have been spontaneously reported during postmarketing surveillance in patients receiving Tromix. Providers should consider the risk of QT prolongation which can be fatal when weighing the risks and benefits of Tromix for at-risk groups including:
- patients with known prolongation of the QT interval, a history of torsades de pointes, congenitallong QT syndrome, bradyarrhythmias or uncompensated heart failure
- patients on drugs known to prolong the QT interval
- patients with ongoing proarrhythmic conditions such as uncorrected hypokalemia or hypomagnesemia, clinically significant bradycardia, and in patients receiving Class IA (quinidine, procainamide) or Class III (dofetilide, amiodarone, sotalol) antiarrhythmic agents.
Elderly patients may be more susceptible to drug-associated effects on the QT interval.
Pregnancy and Lactation
Tromix use may be acceptable during pregnancy. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
It is unknown whether Tromix is excreted into breast milk; use with caution while breastfeeding.
Serious allergic reactions, including angioedema, anaphylaxis, and dermatologic reactions including Stevens-Johnson Syndrome, toxic epidermal necrolysis, and Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) have been reported rarely in patients on Tromix therapy.
Fatalities have been reported. Despite initially successful symptomatic treatment of the allergic symptoms, when symptomatic therapy was discontinued, the allergic symptoms recurred soon thereafter in some patients without further Tromix exposure. These patients required prolonged periods of observation and symptomatic treatment. The relationship of these episodes to the long tissue half-life of Tromix and subsequent prolonged exposure to antigen is presently unknown.
If an allergic reaction occurs, the drug should be discontinued and appropriate therapy should be instituted. Physicians should be aware that allergic symptoms may reappear when symptomatic therapy is discontinued.
Carcinogenesis, Mutagenesis, Impairment Of Fertility
Long-term studies in animals have not been performed to evaluate carcinogenic potential. Tromix has shown no mutagenic potential in standard laboratory tests: mouse lymphoma assay, human lymphocyte clastogenic assay, and mouse bone marrow clastogenic assay. No evidence of impaired fertility due to Tromix was found in rats given daily doses up to 10 mg/kg (approximately 0.2 times an adult daily dose of 600 mg based on body surface area).
Generic Name: Tromix (a ZITH roe MYE sin)Brand Names: Azasite, Tromix 3 Day Dose Pack, Tromix 5 Day Dose Pack, Zithromax, Zithromax TRI-PAK, Zithromax Z-Pak, Zmax
Medically reviewed by Sophia Entringer, PharmD Last updated on Jan 3, 2019.
What is doxycycline? What is Tromix?
Doxycycline is a tetracycline antibiotic used to treat many different types of infections, including respiratory tract infections due to Hemophilus influenzae, Streptococcus pneumoniae, or Mycoplasma pneumoniae. It is used also in the treatment of syphilis, acne, periodontal disease, non-gonococcal urethritis (due to Ureaplasma), Rocky Mountain spotted fever, typhus, chancroid, cholera, brucellosis, and anthrax.
Tromix is a macrolide antibiotic related to erythromycin and clarithromycin (Biaxin) used to treat bacterial infections such as otitis media (infection of the middle ear), tonsillitis, laryngitis, bronchitis, pneumonia, sinusitis, uncomplicated skin and skin structure infections, Mycobacterium avium complex, acute bacterial flare ups of chronic obstructive pulmonary disease (COPD), acute pelvic inflammatory disease, and several sexually transmitted infectious diseases (STDs) such as non-gonococcal urethritis and cervicitis.
Mixing Tromix with herbal remedies and supplements
There are no known problems with taking herbal remedies or supplements alongside Tromix.
Tromix has been reported to be excreted in breast milk in small amounts. Caution should be exercised when Tromix is administered to a nursing woman.