Before Using This Medicine

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 quinine, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to quinine, quinidine (e.g., Quinidex), or to dietary items that contain quinine, such as tonic water or bitter lemon. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Quinine has been used for the treatment of malaria in pregnant women. Treatment is important because if a pregnant woman gets malaria, there is an increased chance of premature births, stillbirths, and abortion. However, quinine has been shown to cause birth defects in rabbits and guinea pigs and has also been shown to cause rare birth defects, stillbirths, and other problems in humans. In addition, quinine has been shown to cause miscarriage when taken in large amounts.

Breast-feeding—Quinine passes into the breast milk in small amounts. However, this medicine has not been reported to cause problems in nursing babies.

Children—This medicine has been used to treat malaria in children and, in effective doses, has not been shown to cause different side effects or problems in children than it does in adults.

Older adults—Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults or if they cause different side effects or problems in older people. There is no specific information comparing use of quinine in the elderly with use in other age groups.

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 quinine, it is especially important that your health care professional know if you are taking the following:

• Mefloquine (e.g., Lariam)—Use of mefloquine with quinine may increase the chance of side effects

Other medical problems—The presence of other medical problems may affect the use of quinine. Make sure you tell your doctor if you have any other medical problems, especially:

• Blackwater fever, history of, or
• Glucose-6-phosphate dehydrogenase (G6PD) deficiency or
• Purpura, or history of (purplish or brownish-red discoloration of skin)—Patients with a history of blackwater fever, G6PD deficiency, or purpura may have an increased risk of side effects affecting the blood

• Heart disease—Quinine can cause side effects affecting the heart, usually at higher doses

• Hypoglycemia—Quinine may cause low blood sugar

• Myasthenia gravis—Quinine may increase muscle weakness in patients with myasthenia gravis