The involvement of the immune system in this putative condition has also been theorized but has never been proven.Purported symptoms of metallosis generally include pain around the site of the implant, pseudotumors (a mass of inflamed cells that resembles a tumor but is actually collected fluids), and a noticeable rash that indicates necrosis. The damaged and inflamed tissue can also contribute to loosening the implant or medical device. Metallosis can cause dislocation of non-cemented implants as the healthy tissue that would normally hold the implant in place is weakened or destroyed. Metallosis has been demonstrated to cause osteolysis.Women, those who are small in stature, and the obese are at greater risk for metallosis because their body structure causes more tension on the implant, quickening the abrasion of the metal components and the subsequent build-up of metallic debris. Physical effects and symptoms
Persons suffering from metallosis can experience any of the following symptoms:

Extreme pain (even when not moving);
Swelling and inflammation;
Loosening of the implant;
Joint dislocation;
Bone deterioration;
Aseptic fibrosis, local necrosis;
Hip replacement failure;
Metal toxicity from grinding metal components; and
Necessary subsequent hip replacement revision or surgeries. Complications
As the grinding components cause metal flakes to shed from the system, the implant wears down. Metallosis results in numerous additional side effects:

Confusion;
Feelings of malaise;
Gastrointestinal problems;
Dizziness;
Headaches;
Problems in the nervous system (feelings of burning, tingling, or numbness of the extremities); and
Cobalt poisoning (skin rashes, cardiomyopathy, problems with hearing, sight or cognition, tremors, and hypothyroidism).
If rifapentine or rifampin are used  in late pregnancy, coagulation should be monitored due to a possible increased risk of maternal postpartum hemorrhage and infant bleeding. Adverse effects
Common side effects include allergic reaction, anemia, neutropenia, elevated transaminases, and pyuria. Overdoses have been associated with hematuria and hyperuricemia. Contraindications
Rifapentine should be avoided in patients with an allergy to the rifamycin class of drugs. This drug class includes rifampicin and rifabutin. Interactions
Rifapentine induces metabolism by CYP3A4, CYP2C8 and CYP2C9 enzymes. It may be necessary to adjust the dosage of drugs metabolized by these enzymes if they are taken with rifapentine. Examples of drugs that may be affected by rifapentine include warfarin, propranolol, digoxin, protease inhibitors and birth control pills. Chemical structure
The chemical structure of rifapentine is similar to that of rifamycin, with the notable substitution of a methyl group for a cyclopentane (C5H9) group. History
Rifapentine was first synthesized in 1965, by the same company that produced rifampicin. The drug was approved by the U.S. Food and Drug Administration (FDA) in June 1998. It is made from rifampicin.Rifapentine was granted orphan drug designation by the FDA in June 1995, and by the European Commission in June 2010. Society and culture
Cancer-causing impurities
In August 2020, the U.S. Food and Drug Administration (FDA) became aware of nitrosamine impurities in certain samples of rifapentine. The FDA and manufacturers are investigating the origin of these impurities in rifapentine, and the agency is developing testing methods for regulators and industry to detect the 1-cyclopentyl-4-nitrosopiperazine (CPNP).