Because vitamin D is fat-soluble, it is hypothesized that absorption would be improved if patients are instructed to take their supplement with a meal. Raimundo et al. performed different studies confirming that a high-fat meal increased the absorption of vitamin D3 as measured by serum 25(OH) D. A clinical report indicated that serum 25(OH) D levels increased by an average of 57% over a 2-month to 3-month period in 17 clinic patients after they were instructed to take their usual dose of vitamin D with the largest meal of the day.Another study conducted in 152 healthy men and women concluded that diets rich in monounsaturated fatty acids may improve and those rich in polyunsaturated fatty acids may reduce the effectiveness of vitamin D3 supplements. In another study performed by Cavalier E. et al., 88 subjects received orally a single dose of 50,000 IU of vitamin D3 solubilized in an oily solution as two ampoules each containing 25,000 IU (D‐CURE®, Laboratories SMB SA, Brussels, Belgium) with or without a standardized high‐fat breakfast. No significant difference between fasting vs. fed conditions was observed. Maintenance phase
Once the desired serum level has been achieved, be it by a high daily or weekly or monthly dose or by a single-dose therapy, the AAP recommendation calls for a maintenance supplementation of 400 IU for all age groups, with this dosage being doubled for premature infants, dark-skinned infants and children, children who reside in areas of limited sun exposure (>37.5° latitude), obese patients, and those on certain medications.
Some evidence indicates it has a genetic basis and is related to chloroquine action with opiate receptors centrally or peripherally. Unpleasant metallic taste
This could be avoided by "taste-masked and controlled release" formulations such as multiple emulsions. Chloroquine retinopathy
Electrocardiographic changesThis manifests itself as either conduction disturbances (bundle-branch block, atrioventricular block) or Cardiomyopathy – often with hypertrophy, restrictive physiology, and congestive heart failure. The changes may be irreversible. Only two cases have been reported requiring heart transplantation, suggesting this particular risk is very low. Electron microscopy of cardiac biopsies show pathognomonic cytoplasmic inclusion bodies. Pancytopenia, aplastic anemia, reversible agranulocytosis, low blood platelets, neutropenia. Pregnancy
Chloroquine has not been shown to have any harmful effects on the fetus when used in the recommended doses for malarial prophylaxis. Small amounts of chloroquine are excreted in the breast milk of lactating women. However, this drug can be safely prescribed to infants, the effects are not harmful. Studies with mice show that radioactively tagged chloroquine passed through the placenta rapidly and accumulated in the fetal eyes which remained present five months after the drug was cleared from the rest of the body. Women who are pregnant or planning on getting pregnant are still advised against traveling to malaria-risk regions. Elderly
There is not enough evidence to determine whether chloroquine is safe to be given to people aged 65 and older. Since it is cleared by the kidneys, toxicity should be monitored carefully in people with poor kidney functions.