Dosing

The dose of a local anesthetic will be different for different patients. Your health care professional will decide on the right amount for you, depending on:

• Your age;
• Your general physical condition;
• The reason the local anesthetic is being given; and
• Other medicines you are taking or will receive before or after the local anesthetic is given.

In deciding to use a medicine, the risks of using the medicine must be weighed against the good it will do. This is a decision you and your medical doctor, dentist, or nurse will make. For local anesthetics, the following should be considered:

Allergies Tell your medical doctor, dentist, or nurse if you have ever had any unusual or allergic reaction to a local anesthetic or to epinephrine (e.g., Adrenalin). Also tell your medical doctor, dentist, nurse, or pharmacist if you are allergic to any other substances, such as sulfites or other preservatives, especially aminobenzoic acid (also called para-aminobenzoic acid [PABA]).

Pregnancy Local anesthetics have not been reported to cause birth defects in humans.

Use of a local anesthetic during labor and delivery may rarely cause unwanted effects. These medicines may increase the length of labor by making it more difficult for the mother to bear down (push). They may also cause unwanted effects in the fetus or newborn baby, especially if certain medical problems are present at the time of delivery. Before receiving a local anesthetic for labor and delivery, you should discuss with your doctor the good that this medicine will do as well as the risks of receiving it.

Breast-feeding It is not known whether local anesthetics pass into breast milk. However, these medicines have not been reported to cause problems in nursing babies.

Children Children may be especially sensitive to the effects of parenteral-local anesthetics. This may increase the chance of side effects.

Older adults Elderly people are especially sensitive to the effects of parenteral-local anesthetics. This may increase the chance of side effects.

Other medicines Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your medical doctor, dentist, or nurse may want to change the dose, or other precautions may be necessary. It is very important that you tell the person in charge if you are taking:

• Beta-adrenergic blocking agents (carteolol [e.g., Cartrol], carvedilol [e.g., Coreg], labetolol [e.g., Normodyne], nadolol [e.g., Corgard], oxprenolol [e.g., Trasicor], penbutolol [e.g., Levatol], pindolol [e.g., Visken], propranolol [e.g., Inderal], sotalol [e.g., Sotacor], timolol [e.g., Blocadren]) or
• Carteolol (ophthalmic) (e.g., Ocupress) or
• Levobunolol (ophthalmic) (e.g., Betagan) or
• Metipranolol (ophthalmic) (e.g., OptiPranolol) or
• Timolol (ophthalmic) (e.g., Timoptic) Use of some local anesthetics with these medicines may increase the risk of high blood pressure or a slow heart rate

• Central nervous system (CNS) depressants (medicines that cause drowsiness) Use of local anesthetics with these medicines may increase the risk that drowsiness will occur

• Digoxin (e.g., Lanoxin) Use of some local anesthetics with this medicine may increase the risk of irregular heartbeats

• Haloperidol (e.g., Haldol) or
• Phenothiazines (e.g., Phenergan) Use of these medicines may reduce the effectiveness of the local anesthetic

• Tricyclic antidepressants (amitriptyline [e.g., Elavil], amoxapine [e.g., Asendin], clomipramine [e.g., Anafranil], desipramine [e.g., Norpramin], doxepin [e.g., Sinequan], imipramine [e.g., Tofranil], nortriptyline [e.g., Aventyl], protriptyline [e.g., Vivactil], trimipramine [e.g., Surmontil]) or
• Maprotiline (e.g., Ludiomil) Use of some local anesthetics with these medicines may increase the chance of some problems, including high blood pressure and irregular heartbeats

• Any other medicine, prescription or nonprescription (over-the-counter [OTC]), or
• ``Street'' drugs, such as amphetamines (``uppers''), barbiturates (``downers''), cocaine (including ``crack''), marijuana, phencyclidine (PCP, ``angel dust''), and heroin or other narcotics Serious side effects may occur if anyone gives you a local anesthetic without knowing that you have taken another medicine

• Asthma Increased chance of allergic-like reactions with use of some local anesthetics

• Brain infection or tumor or
• Blood clotting disorders Increased chance of bleeding with injection of local anesthetics

• Diabetes mellitus (sugar diabetes) Use of local anesthetics can cause stress on your heart if you have diabetes mellitus

• Heart disease Use of local anesthetics can worsen some kinds of heart disease

• History of migraine headaches Use of local anesthetics can worsen headaches

• Hypertension (high blood pressure) or
• Hypotension (low blood pressure) Use of local anesthetics can cause hypotension or hypertension

• Hyperthyroidism Use of some local anesthetics can cause stress on your heart if you have hyperthyroidism

• Kidney disease or
• Liver disease Increased chance of side effects

• Methemoglobinemia Prilocaine may make this condition worse

• Peripheral vascular disease Use of some local anesthetics can make this condition worse or can cause your blood pressure to increase

• Skin infection or inflammation Your physician may not want to inject the local anesthetic into infected or inflamed skin because the local anesthetic may not work as well