Medical Infusion Therapy: What It Is and What to Expect

Infusion therapy is a procedure in which medications are delivered directly into the bloodstream, usually with a needle and catheter that's inserted into a vein.

Infusion therapy is needed when a patient cannot take a drug orally. It's also a method of delivering medications in larger or more controlled amounts, such as during chemotherapy for cancer or with pain medication during childbirth.

You can get infusion therapy in a medical setting or at home. Insulin shots are an example of home infusion therapy.

This article explains the uses, benefits, and potential side effects of different kinds of infusion therapy.

Types of Infusion Therapy and Conditions Treated

The types of infusion therapy include:

• Intravenous (IV)
• Epidural
• Intramuscular
• Subcutaneous

Intravenous (IV)

Intravenous therapy is when medications or fluids are injected directly into the bloodstream. IV therapy is commonly used for:

• Maintaining fluids in the body after dehydration, diarrhea, vomiting, or surgery
• Chronic conditions, such as chemotherapy or immunotherapy for cancer
• Antibiotic therapy (to treat conditions such as Lyme disease and meningitis)
• Administering anesthesia before surgery
• Blood transfusions
• Providing nutrients, like iron and B vitamins, when they are chronically low

Epidural

An epidural is a type of infusion therapy that is inserted around the spinal nerves in the lower back. Epidurals block pain signals from being sent from the spine to the brain. An epidural can administer the following:

• Analgesia (pain relief)
• Anesthesia (numbing)
• Steroids for pain, as with acute back pain

Epidurals are best known as a way to prevent or numb the pain of childbirth, but they can also be used to prevent pain during and after surgery. Epidurals might also help relieve acute pain.

Intramuscular

Intramuscular infusion therapy involves medication inserted into muscle tissue. Uses of intramuscular infusion therapy include:

• Hormone therapy, such as testosterone or estrogen injections for cancer treatment
• Antibiotics to treat conditions like gonorrhea and syphilis
• Vaccines against conditions like diphtheria-tetanus-pertussis (DTaP, Tdap) and Covid-19
• Antibodies (immunoglobulins), which are proteins made by cells to help the immune system fight bacteria, viruses, or other harmful substances

Subcutaneous

Subcutaneous infusion therapy involves drugs injected into fat underneath the skin. Subcutaneous injection sites include the upper arms, stomach, upper thighs, lower back, and buttocks. Subcutaneous therapy includes:

• Insulin therapy for diabetics
• Opioids for pain relief
• Allergy medications like epinephrine
• Heparin, a medication used to prevent blood clots

Benefits of Infusion Therapy

The benefits of infusion therapy include:

• Fast-acting relief, especially in emergency situations, like after an allergic reaction or during childbirth
• Medication for those who cannot take pills orally
• Administering larger and/or controlled amounts of medication
• Intramuscular and subcutaneous injections help drugs remain in the body longer
• High success rates for several conditions

Infusion Therapy Success Rates

Several studies have shown high success rates for infusion therapies. For example:

• Epidurals are about 98%–99% successful in relieving pain for people giving birth.
• Monoclonal antibody treatments for COVID-19 reduced viral burden—the amount of virus healthcare providers can find in your body—by 90% in trial participants, and emergency room visits and infection time were cut by almost half. However, most of the monoclonal antibodies authorized for treating or preventing COVID-19 have been revoked due to limited effectiveness against newer variants.
• Ketamine infusion therapy could be a fast and effective treatment for chronic depression, with about half of patients in one study responding to treatment.
• Some cancers respond better to chemotherapy, a type of infusion therapy that kills harmful cells, than others. For example, a recent study found prostate cancer patients were about 10% more likely to survive with chemotherapy than other cancer treatments. However, there are other infusion therapies available to treat cancer that have fewer side effects than chemotherapy. These include hormone therapy and antibodies. It also encompasses vaccines and immunotherapy.

How to Prepare and What to Expect

To prepare for infusion therapy, ask your practitioner about the following:

• If you have to avoid any foods or modify your medication schedule before treatment
• If others are allowed to come with you to the procedure
• If there will be pain and something to relieve that pain
• What will be used to treat allergic reactions if they arise
• How many sessions are required for treatment
• Any side effects you should monitor at home
• How many training sessions you and your caregivers will receive for home infusion therapy
• How to measure medications accurately for home infusion therapy

Expect the following during infusion therapy:

• There will be a comfortable chair to rest in throughout the treatment
• The injection site and needles will be disinfected
• Anesthesia may be used when larger needles are necessary during treatment
• You will be monitored throughout your therapy
• The injection site will be covered after your treatment
• You and your caregiver(s) will receive adequate training and follow-up appointments for home fusion

How long infusion therapy takes depends on the condition being treated. Chemotherapy for cancer, for example, can take about three to six months. Epidurals, on the other hand, last about one to two hours. Hormone therapy for prostate cancer can last months to years and ketamine infusions can last anywhere from 30 minutes to several hours.

Side Effects of Infusion Therapy

Infusion therapy side effects might include:

• Redness at the site of injection
• Swelling
• Injury at the injection site
• Muscle pain
• Allergic reactions like rash, difficulty breathing, and confusion

The following are some risks associated with each type of infusion therapy.

IV Therapy Complications

IV therapy complications may include:

• Burning, stinging, or redness if IV solution leaks onto skin surrounding the injection site
• Pus leaking from injection if infected
• Pulmonary edema, or excess lung fluid: This requires quick medical attention and is marked by shortness of breath and coughing up a frothy substance.
• Air embolism (when air enters the vein): Symptoms include shortness of breath, increased heart rate, shoulder pain, light-headedness, and confusion.

Epidural Therapy Complications

Epidural therapy complications may include:

• Low blood pressure
• Headache
• Hot flashes
• Damaged blood vessel
• Damage to injection site nerves
• Losing bladder and bowel control

Intramuscular Therapy Complications

Intramuscular therapy complications may include:

• Nerve damage
• Medication leaking into surrounding tissue
• Muscle atrophy, or when a muscle loses strength
• Bone injury

Subcutaneous Therapy Complications

Subcutaneous therapy complications may include:

• Blister at injection site
• Headache
• Sore throat
• Nausea
• Kidney problems
• Blood clots

Summary

Infusion therapy involves a medication or nutrient inserted directly into a person's system. Infusion therapy can be intravenous (IV), meaning through an IV needle; an epidural, which is inserted around nerves in the spinal cord; intramuscular, which is inserted in muscle tissue; or subcutaneous, inserted into body fat under the skin.