Precautions/ Contraindications These are conditions (diseases, age, pregnancy, lactation) that make it risky or completely unsafe for clients to take specific medications. For example, tetracyclines can stain developing teeth. Therefore, children younger than 8 years should not take these medications. Another example is that myasthenia gravis is a contraindication for fentanyl, an opioid analgesic. Some medications require caution with some conditions. For example, the kidneys excrete vancomycin without changing it. Therefore, renal impairment requires caution when administering this medication.
Preparation, dosage, administration It is important to know any specific considerations for preparation, safe dosages, dosage calculations, and how to administer the medication. For example, morphine is available in many formulations. Oral doses of morphine are generally higher than parenteral doses due to extensive first‑pass effect. Clients who have chronic, severe pain, such as with cancer, generally take oral doses of morphine.