It is safe for use in pregnancy as it does not reduce placental blood flow. Ephedrine is generally available in 25 or 30 mg ampoules. Its effect generally lasts about 10 minutes and it may need repeating. Alternatively, the ampoule may be added to a bag of intravenous fluid and the rate of infusion altered to maintain the desired blood pressure. It can also be given intramuscularly but its onset time is delayed although its duration is prolonged.
Larger doses are necessary when it is given intramuscularly.
It is available in 20mg ampoules and is best diluted before injection. Suitable adult doses are 2.5-5mg. It is a pure peripheral vasoconstrictor and reflex bradycardia, needing treatment with atropine can occur. A pure peripheral vasoconstrictor which is available in 10mg ampoules. Dilute before use.