Half and half nails (also known as "Lindsays nails") show the proximal portion of the nail white and the distal half red, pink, or brown, with a sharp line of demarcation between the two halves. : 785   Seventy percent of hemodialysis patients and 56% of renal transplant patients have at least one type of nail abnormality. Absence of lunula, splinter hemorrhage, and half and half nails were significantly more common in hemodialysis patients, while leukonychia was significantly more common in transplant patients. : 785 : 659

See also
List of cutaneous conditions

References


== External links ==
Escherichia coli
Proteus mirabilis
Klebsiella pneumoniae
Enterobacter species
Coagulase-negative Staphylococcus species, including S. saprophyticus
Streptococcus pneumoniae
Haemophilus influenzae

Side effects
Common
Nauseas
Change in taste
Vomiting
Diarrhea
Rashes
Sun sensitivity
Itchiness

Rare
Can cause thrombocytopenia (low levels of platelets) by lowering folic acid levels; this may also cause megaloblastic anemia. Trimethoprim antagonizes the epithelial sodium channel  in the distal tubule, thus acting like amiloride. This can cause increased potassium levels in the body (hyperkalemia). Can compete with creatinine for secretion into the renal tubule. This can cause an artificial rise in the serum creatinine. Use in EHEC infections may lead to an increase in expression of Shiga toxin. Contraindications
Known hypersensitivity to trimethoprim
History of megaloblastic anemia due to folate deficiency

Pregnancy
Based on the studies that show that trimethoprim crosses the placenta and can affect folate metabolism, there has been growing evidence of the risk of structural birth defects associated with trimethoprim, especially during the first trimester of pregnancy. It may be involved in a reaction similar to disulfiram when alcohol is consumed after it is used, in particular when used in combination with sulfamethoxazole. The trophoblasts in the early fetus are sensitive to changes in the folate cycle. A recent study has found a doubling in the risk of miscarriage in women exposed to trimethoprim in the early pregnancy. Mechanism of action
Trimethoprim binds to dihydrofolate reductase and inhibits the reduction of dihydrofolic acid (DHF) to tetrahydrofolic acid (THF). THF is an essential precursor in the thymidine synthesis pathway and interference with this pathway inhibits bacterial DNA synthesis.