The common side effects of oxymetholone include depression , lethargy , headache , swelling , rapid weight gain , priapism , changes in skin color, urination problems, nausea , vomiting , stomach pain (if taken on an empty stomach), loss of appetite , jaundice , breast swelling in men, feeling restless or excited, insomnia , and diarrhea .  In women, side effects also include acne , changes in menstrual periods , voice deepening , hair growth on the chin or chest , pattern hair loss , enlarged clitoris , and changes in sex drive .   Because of its 17α-alkylated structure, oxymetholone is hepatotoxic .  Long term use of the drug can cause a variety of serious ailments, including hepatitis , liver cancer , and cirrhosis ; therefore periodic liver function tests are recommended for those taking oxymetholone. 
Results from randomized controlled trials in patients with first acute renal allograft rejection episodes refractory to conventional steroid therapy have demonstrated that ATGAM, when administered in conjunction with standard therapy, yields efficacy results superior to those of standard therapy alone. One study investigated two different regimens of ATGAM; immediate and delayed therapy. Patients were enrolled at the time of first rejection episode and randomized among three treatment groups: control (no ATGAM), immediate ATGAM, and delayed ATGAM. Patients in all three treatment groups received standard rejection therapy in the form of bolus doses of Solu-Medrol®15 mg/kg/day IV, while patients in the two ATGAM groups received ATGAM therapy in addition to Solu-Medrol®. In the immediate ATGAM group, ATGAM administration started at the time of diagnosis of rejection (concurrent with standard therapy). In the delayed ATGAM group, ATGAM administration started on rejection day 4 (following the first three doses of Solu-Medrol®). Patients in both of the treated groups received from 10 to 21 doses of ATGAM. Results favored the two ATGAM groups (and particularly the immediate ATGAM group) in both outcome of first rejection and functional graft survival. The improvement in functional graft survival was statistically significant (p=). There was also a statistically significant difference in patient survival rate favoring the ATGAM-treated groups (p=).
It should be noted that in theory if one was to consistently suppress your natural estrogen levels for a long period of time, this would negatively impact your health, including your cholesterol. Due to the ability of Letrozole- to inhibit estrogen so much, this should definitely be a concern to most users. However the research that has focused on the relationship between use of letrozole and cholesterol levels is rather inconsistent in it's findings. Many studies have concluded that the compound is detrimental to both a user's HDL and LDL cholesterol levels, while other research has found no link. Obviously individuals are best served to monitor their cholesterol while using any compound via blood tests however barring that, letrozole should simply not be run for extended periods of time if at all possible. Doing so could cause serious medical complications.
Along with the issues related to blood lipids is the fact that many users complain that their libido is dramatically reduced when using the compound. This is related to the fact that estrogen is partly responsible for the regulation of an individual's sex drive. Since Letrozole- is so potent it can often drive estrogen levels too low and this inhibits a user's libido. To avoid this users can lower dosages, but some anecdotally report that even extremely low doses of the drug can cause problems. If this is the case a less potent compound such as exemestane or anastrozole may be a more appropriate option.