Take this medication by mouth with a meal and a full glass of water (8 ounces/240 milliliters) as directed by your doctor, usually once or twice daily. Do not crush the tablets. If you have trouble swallowing the tablets whole, you may dissolve the tablets in a glass of water or apple juice. The amount of liquid will depend on your dose. Consult your doctor or pharmacist for more detailed instructions. Stir the mixture well until the tablet(s) dissolve, and drink right away.

The dosage is based on your medical condition, response to treatment, and other medications you may be taking. Children's dosage is also based on body size. Be sure to tell your doctor and pharmacist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

Avoid eating grapefruit or drinking grapefruit juice while using this medication unless your doctor or pharmacist says you may do so safely. Grapefruit can increase the chance of side effects with this medicine. Ask your doctor or pharmacist for more details.

Do not increase your dose or use this drug more often or for longer than prescribed. Your condition will not improve any faster, and your risk of side effects will increase.

Since this drug can be absorbed through the skin and lungs and may harm an unborn baby, women who are pregnant or who may become pregnant should not handle this medication or breathe the dust from the tablets.