What Is It, Really?

Roxithromycin is a macrolide antibiotic. It is currently being sold by the PWA Health Group as a possible treatment for cryptosporidiosis, based on two small open-label studies. Cryptosporidiosis, a parasitic infection, often leads to severe diarrhea and weight loss and is potentially fatal. Unfortunately, there is no standard treatment for cryptosporidiosis. Roxithromycin is widely used in Latin America and Europe as a safe and effective treatment for a number of bacterial infections.

How Does It Work

Roxithromycin is very similar in composition, chemical structure (semi-synthetic) and mechanism of action to erythromycin, azithromycin, or clarithromycin. Antibiotics such as roxithromycin can often be prescribed for several different infections, including some STDs, upper and lower respiratory tract infections and asthma, gum infections like gingivitis, and bacterial infections associated with stomach and intestinal ulcers. Roxithromycin is absorbed well into the gastro-intestinal tract, with few side effects, and actively responds to the presence of cryptosporidium, pneumocystis carinii (PCP), toxoplasma gondii, and Mycobacterium Avium (MAC).

Clinical Studies

While there have been many trials that have reported the effectiveness of roxithromycin in treating various parasitic and bacterial infections, these have mostly been in non-HIV+ people. In HIV+ people, two trials have been completed to determine the effect of roxithromycin on cryptosporidiosis. However, both of these trials are small and uncontrolled. We hope that roxithromycin will be studied in HIV+ people, in a larger, controlled trial for cryptosporidiosis. Roxithromycin and cryptosporidiosis: At the 1994 International Conference on AIDS in Japan, results from a nine person study being treated for AIDS-related cryptosporidiosis were announced. Each of the PWAs received one 300 mg tablet, twice daily, for 4 weeks. After 2 weeks, complete clearance (no diarrhea, negative cryptosporidium stood cultures) were reported in 5 participants. A partial response (diarrhea improvement and decreased cryptosporidium culture) was reported in 3 participants, with no improvement reported in one participant. An earlier, even smaller trial of roxithromycin reported significant response in four participants. In this trial, four PWAs also took 300 mg of roxithromycin, twice daily, for two weeks. All participants were successfully treated for diarrhea, with improvements being reported in as little as two days upon starting treatment. Upon completion of the trial, 3 of the 4 participants were negative for cryptosporidium cultures. While the remaining participant showed initial diarrhea remission, it had recurred after the treatment ended.

What about other OIs?

Roxithromycin and MAC: There has been one report of roxithromycin being effective in treating mycobacterium avium complex (MAC) in the test tube. Roxithromycin showed antibacterial activity against all the MAC specimens (three specimens were from HIV+ persons, two were from HIV- persons). While the test tube data is certainly something to be optimistic about, it is critical that the manufacturer begin studies in humans to determine roxithromycin's effectiveness in treating disseminated MAC.

Roxithromycin and toxoplasmosis: In 1989, a report announced the failure of roxithromycin in treating AIDS-related toxoplasmosis. Like cryptosporidiosis, toxoplasmosis is a parasitic infection. Unlike cryptosporidiosis, toxoplasmosis usually affects the brain, sometimes leading to coma and seizures. In 1995, a study in 52 patients showed that 300 mg roxythromycin given once a week could prevent PCP and toxoplasmosis. 15% of the patients stopped the drug because of side effects like stomach ache, nausea, and raised transaminases.

Other Studies

Roxithromycin has been studied and used for a number of different parasitic/bacterial infections in non HIV-infected people. Successful treatment of various infections has been reported, including: chlamydia, sinusitis, bacterial-associated respiratory disease, oral (odontogenic) infections, pneumonia, and skin infections(erysipelas). When studied as treatment for Lyme borreliosis (Lyme's disease) and tuberculosis, roxithromycin was not demonstrated to be an effective treatment.


Cryptosporidium parvum is a single-cell parasite that produces chronic watery diarrhea in people with compromised immune systems. This infection can be fatal for HIV+ people with severely suppressed immune systems. Because diarrhea can be attributed to an number of different factors in PWAs, a diagnosis of cryptosporidiosis is confirmed by a fecal smear or intestinal biopsy. The disease is highly infectious; it is transmitted from person to person or animal to person. Recently, trace amounts of cryptosporidia have been found in New York City's water supply. One organism per 100 gallons of water has been isolated, which can be dangerous for people with severely suppressed immune systems.

Treatments for cryptosporidiosis: The response to treatment of cryptosporidium infection has been abysmal among people with HIV. As previously indicated, there is no standard treatment for cryptosporidiosis. A number of different drugs are currently being investigated as a possible treatment for cryptosporidiosis. NTZ, azithromycin, paromomycin, letrazuril, IGX-CP (Hyperimmune Egg Yolks) and octreotide acetate are currently being studied as possible treatments for cryptosporidiosis. Studies to date on these treatments have shown only moderate results in treating cryptosporidiosis. A sixth compound, BACI(Bovine anti-Cryptosporidium Immunoglobulin), a drug designed specifically to combat cryptosporidium, failed to demonstrate any effectiveness in a phase I clinical trials.

To learn more about clinical trials that may be open for the treatment of cryptosporidiosis, call the National Institutes of Health's clinical trials information line at 1-800-TRIALS-A.

Side Effects and Toxicity

There have been very few reports of side effects when being treated with roxithromycin. While we do not have much data on its side effects in HIV+ people, we know that it is a treatment of choice in Latin America and Europe due to its higher safety profile over similar antibiotics. Possible side effects of roxithromycin include: nausea, vomiting, indigestion, cramps, etc. Elevation of liver enzymes have also been reported. The 1994 open label trial reported a moderate to severe rise in liver enzymes. Thus, it is crucial to have Liver Function Tests (LFTs) monitored carefully when taking roxithromycin.

As with other antibiotics, roxithromycin is a broad spectrum antibiotic that may upset the natural balance of useful flora, the body's natural response to fungal infection. Antibiotics are known to predispose healthy women to vaginal candidiasis. Several studies of antibiotic treatments for a variety of opportunistic infections have reported that antibiotics aggravate vaginal and oral thrush.


According to the two studies in PWAs, the current recommended dose in 300 mg, twice a day. Like most antibiotics, roxithromycin should be taken for a minimum of five days to effectively treat the infection and to prevent resistance. Dosing schedules and duration should be discussed with your doctor. It is important that roxithromycin be taken at least fifteen minutes after meals. This will allow the drug to have maximum absorption in the body.

What We Carry

We import Rulid brand roxithromycin made by Albert-Roussel Pharma GmbH from Germany. It comes in boxes of 10 tablets of 300 mg each. Under the recommended dosing guidelines, one box will last 3-10 days.