In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For narcotic analgesics, the following should be considered:

Allergies Tell your doctor if you have ever had any unusual or allergic reaction to any of the narcotic analgesics. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy Although studies on birth defects with narcotic analgesics have not been done in pregnant women, these medicines have not been reported to cause birth defects. However, hydrocodone, hydromorphone, and morphine caused birth defects in animals when given in very large doses. Buprenorphine and codeine did not cause birth defects in animal studies, but they caused other unwanted effects. Butorphanol, nalbuphine, pentazocine, and propoxyphene did not cause birth defects in animals. There is no information about whether other narcotic analgesics cause birth defects in animals.

Too much use of a narcotic during pregnancy may cause the baby to become dependent on the medicine. This may lead to withdrawal side effects after birth. Also, some of these medicines may cause breathing problems in the newborn infant if taken just before delivery.

Breast-feeding Most narcotic analgesics have not been reported to cause problems in nursing babies. However, when the mother is taking large amounts of methadone (in a methadone maintenance program), the nursing baby may become dependent on the medicine. Also, butorphanol, codeine, meperidine, morphine, opium, and propoxyphene pass into the breast milk.

Children Breathing problems may be especially likely to occur in children younger than 2 years of age. These children are usually more sensitive than adults to the effects of narcotic analgesics. Also, unusual excitement or restlessness may be more likely to occur in children receiving these medicines.

Older adults Elderly people are especially sensitive to the effects of narcotic analgesics. This may increase the chance of side effects, especially breathing problems, during treatment.

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 doctor may want to change the dose, or other precautions may be necessary. When you are taking a narcotic analgesic, it is especially important that your health care professional know if you are taking any of the following:

• Carbamazepine (e.g., Tegretol) Propoxyphene may increase the blood levels of carbamazepine, which increases the chance of serious side effects

• Central nervous system (CNS) depressants or
• Monoamine oxidase (MAO) inhibitor activity (isocarboxazid [e.g., Marplan], phenelzine [e.g., Nardil], procarbazine [e.g., Matulane], tranylcypromine [e.g., Parnate] (taken currently or within the past 2 weeks) or
• Tricyclic antidepressants (amitriptyline [e.g., Elavil], amoxapine [e.g., Asendin], clomipramine [e.g., Anafranil], desipramine [e.g., Pertofrane], doxepin [e.g., Sinequan], imipramine [e.g., Tofranil], nortriptyline [e.g., Aventyl], protriptyline [e.g., Vivactil], trimipramine [e.g., Surmontil]) The chance of side effects may be increased; the combination of meperidine (e.g., Demerol) and MAO inhibitors is especially dangerous

• Naltrexone (e.g., Trexan) Narcotics will not be effective in people taking naltrexone

• Rifampin (e.g., Rifadin) Rifampin decreases the effects of methadone and may cause withdrawal symptoms in people who are dependent on methadone

• Zidovudine (e.g., AZT, Retrovir) Morphine may increase the blood levels of zidovudine and increase the chance of serious side effects

• Alcohol abuse, or history of, or
• Drug dependence, especially narcotic abuse, or history of, or
• Emotional problems The chance of side effects may be increased; also, withdrawal symptoms may occur if a narcotic you are dependent on is replaced by buprenorphine, butorphanol, nalbuphine, or pentazocine

• Brain disease or head injury or
• Emphysema, asthma, or other chronic lung disease or
• Enlarged prostate or problems with urination or
• Gallbladder disease or gallstones Some of the side effects of narcotic analgesics can be dangerous if these conditions are present

• Colitis or
• Heart disease or
• Kidney disease or
• Liver disease or
• Underactive thyroid The chance of side effects may be increased

• Convulsions (seizures), history of Some of the narcotic analgesics can cause convulsions