Up to 12% of pentamidine is eliminated in the urine unchanged.Elimination: Pentamidine has an average half-life of 5–8 hours when given intravenously and 7–11 hours when given intramuscularly. However, these may increase with severe kidney problems. Pentamidine can remain in the system for as long as 8 months after the first injection. Chemistry
Pentamidine isethionate for injection is commercially available as a lyophilized, white crystalline powder for reconstitution with sterile water or 5% Dextrose. After reconstitution, the mixture should be free from discoloration and precipitation. Reconstitution with sodium chloride should be avoided due to formation of precipitates. Intravenous solutions of pentamidine can be mixed with intravenous HIV medications like zidovidine and intravenous heart medications like diltiazem. However, intravenous solutions of antiviral foscarnet and antifungal fluconazole are incompatible with pentamidine. To avoid side-effects associated with intravenous administration, the solution should be slowly infused to minimize the release of histamine. History
Pentamidine was first used to treat African trypanosomiasis in 1937 and leishmaniasis in 1940 before it was registered as pentamidine mesylate in 1950. Its efficacy against Pneumocystis jirovecii was demonstrated in 1987, following its re-emergence on the drug market in 1984 in the current isethionate form.
Treatment
Avoidance and Hearing Protection
Setback prevention and reduction of pain symptoms are high priorities among those with hyperacusis and noxacusis, which is often managed through a combination of controlling the environment so as to avoid loud sounds, soundproofing, and wearing hearing protection, such as earplugs and/or safety earmuffs, such as the type used at firing ranges or industrial applications

Diet
Diet may play a role in symptom management in some cases of hyperacusis, with response to a migraine diet, low-histamine diet, or low sodium diet. Sound Therapy
Sound therapy is sometimes recommended for those with hyperacusis, though its application among those with pain (noxacusis) should be used with caution. Tinnitus retraining therapy, a treatment originally used to treat tinnitus, uses broadband noise to treat hyperacusis. Pink noise can also be used to treat hyperacusis. By listening to broadband noise at soft levels for a disciplined period of time each day, some patients can rebuild (i.e., re-establish) their tolerances to sound. More research is needed on the efficacy of sound therapy techniques when hyperacusis is the primary complaint, rather than a secondary symptom, indicating that "no strong conclusions can be made" about its efficacy at this time. Cognitive Behavioral Therapy
Another possible treatment is cognitive behavioral therapy (CBT), which may also be combined with sound therapy. However, randomized controlled trials with active control groups are still needed to establish the effectiveness of CBT for hyperacusis and the usefulness of CBT for noxacusis (pain hyperacusis) is not yet demonstrated in the scientific literature.