No dose adaptation is necessary for elderly or renally (kidney) impaired patients.Loratadine is usually compatible with breastfeeding (classified category L-2 - probably compatible, by the American Academy of Pediatrics). In the U.S., it is classified as category B in pregnancy, meaning  animal reproduction studies have failed to demonstrate a risk to the fetus, but no adequate and well-controlled studies in pregnant women have been conducted. Adverse effects
As a "non-sedating" antihistamine, loratadine causes less (but still significant, in some cases) sedation and psychomotor retardation than the older antihistamines, because it penetrates the blood/brain barrier less.Other side effects include headache and antimuscarinic effects, such as urinary retention, dry mouth, blurred vision, and gastrointestinal problems. Interactions
Substances that act as inhibitors of the CYP3A4 enzyme such as ketoconazole, erythromycin, cimetidine, and furanocoumarin derivatives (found in grapefruit) lead to increased plasma levels of loratadine — that is, more of the drug was present in the bloodstream than typical for a dose. This had clinically significant effects in controlled trials of 10 mg loratadine treatment Antihistamines should be discontinued 48 hours prior to skin allergy tests, since these drugs may prevent or diminish otherwise-positive reactions to dermal activity indicators. Pharmacology
Pharmacodynamics
Loratadine is a tricyclic antihistamine, which acts as a selective inverse agonist of peripheral histamine H1 receptors. The potency of second generation histamine antagonists is (from strongest to weakest) desloratadine (Ki 0.4 nM) > levocetirizine (Ki 3 nM) > cetirizine (Ki 6 nM) > fexofenadine (Ki 10 nM) > terfenadine > loratadine.
Periungual warts are warts that cluster around the fingernail or toenail. They appear as thickened, fissured cauliflower-like skin around the nail plate. Periungual warts often cause loss of the cuticle and paronychia. Nail biting increases susceptibility to these warts.Warts of this kind often cause damage to the nail either by lifting the nail from the skin or causing the nail to partially detach. If they extend under the nail, then the patient may suffer pain as a result. Sometimes periungual wart infections resemble the changes that are found in onychomycosis. In worst cases, if the infection causes injury or damage to the nail matrix, deformity in the nail may become permanent. As with other wart types, a number of treatments are available, including laser therapy, cryotherapy, salicylic acid, and other topical treatments. == References ==