Indications
L-Phenylalanine is an essential amino acid, which means the body cannot make it and must get it from food or feeding. It is used to build proteins and is converted into Tyrosine, which the body needs to make thyroid hormones, the skin pigment melanin and brain messengers such as dopamine and noradrenaline. In medicines it is one of the building blocks in amino acid solutions given by intravenous drip (parenteral nutrition) to people who cannot eat or absorb enough food, for example after major surgery, in severe illness, burns, or bowel failure. It is not used on its own as a medicine for any illness.
How It Works
Amino acids are the units from which the body builds proteins for muscles, organs, enzymes, immune defences and wound healing. When given in a drip together with other amino acids, glucose, fats, minerals and vitamins, L-Phenylalanine helps supply what the body needs to keep up protein building and prevent muscle loss while normal eating is not possible.
Dosage and Administration
It is given by a doctor or nurse as part of a ready-made amino acid infusion into a vein. The amount and rate of the whole solution are worked out by the medical team from body weight, age, illness, kidney and liver function, and blood tests, as prescribed. It is never used at home without specialist supervision.
Interactions
Direct interactions with other medicines are not expected. However, other medicines, electrolytes or vitamins should only be added to the infusion bag by the pharmacy or medical team when they are known to be compatible, because mixing can make the solution unstable.
Contraindications
- Phenylketonuria (PKU), an inherited condition in which phenylalanine cannot be broken down.
- Inherited disorders of amino acid metabolism.
- Severe liver failure or hepatic coma.
- Severe kidney failure without dialysis.
- Fluid overload, uncorrected shock, or severe uncorrected acid or salt imbalance.
- Known allergy to any component of the infusion.
Side Effects
Side effects are usually related to the infusion as a whole. They may include pain, redness or swelling of the vein at the drip site, nausea, flushing, fever or chills, and changes in blood sugar, salts or liver tests. Infection of the drip line can occur.
Tell the nurse or doctor immediately if you have fever with shivering, pain or swelling where the drip enters, shortness of breath, swelling of the face or body, chest discomfort, or confusion.
Pregnancy and Lactation
Amino acids are normal nutrients. Amino acid infusions may be given during pregnancy and breastfeeding when nutrition by mouth is not enough, under close medical supervision.
Precautions and Warnings
- Blood sugar, salts, fluid balance, and kidney and liver function are checked regularly during treatment.
- The infusion is given slowly and with strict sterile technique.
- Extra care is needed in babies, older people, and those with heart, kidney or liver disease.
- Hospital-only product.
Overdose
Giving the infusion too fast or in too large an amount can cause nausea, vomiting, flushing, chills, fluid overload, raised blood ammonia or acid build-up. The medical team will slow or stop the infusion and treat the effects.
Therapeutic Class
Amino acid (parenteral nutrition component)
Storage
Hospital product: store as directed on the pack, usually below 25°C, protected from light. Do not freeze. Keep out of the reach of children.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.