Permethrin comes as a cream to apply to the skin. Over-the-counter permethrin comes as a lotion to apply to the scalp and hair. Permethrin cream is usually applied to the skin in one treatment, but occasionally a second treatment is necessary. Permethrin lotion is usually applied to the skin in one or two treatments, but occasionally three treatments are necessary. If live mites are seen two weeks (14 days) after the first treatment with permethrin cream, then a second treatment should be applied. If live lice are seen one week after the first treatment with over-the-counter permethrin lotion, then a second treatment should be applied. Follow the directions on your prescription label or the package label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Use permethrin exactly as directed. Do not use more or less of it or use it more often than prescribed by your doctor.
Physicians should educate pregnant patients about the harmful effects of smoking to themselves and the developing fetus, and help these patients develop a plan for smoking cessation. The safety of nicotine replacement products in pregnancy has not been adequately studied. However, smoking is likely to be more harmful than nicotine replacement therapy, particularly because cigarette smoke contains more than 3,000 different chemicals that can potentially harm humans, and one of the main components of cigarette smoke is carbon monoxide, a known fetal toxin. Therefore, it is reasonable to consider the use of nicotine replacement products in patients who cannot maintain smoking abstinence without pharmacologic intervention.
Studies show some of the chemicals in coal tar may cause cancer, but only in very high concentrations, such as in what is used in industrial paving. Anyone using tar regularly should follow a regular skin cancer checkup schedule. California requires OTC coal tar shampoos, lotions and creams that contain more than percent coal tar to be labeled with cancer warnings. However, the FDA maintains that OTC products with coal tar concentrations between percent and 5 percent are safe and effective for psoriasis, and there is no scientific evidence that the tar in OTC products is carcinogenic.