Alpha-1-Proteinase Inhibitor: uses, weekly infusions, side effects
Last updated September 7, 2026.
**Alpha-1-proteinase inhibitor (human) is a plasma-derived protein given by vein to replace a missing enzyme blocker in people with severe alpha-1 antitrypsin deficiency, a class of treatment called augmentation therapy.** Alpha-1 antitrypsin is the body's main brake on neutrophil elastase, an enzyme released in the lungs that breaks down elastic tissue. When your genes leave you with very little of that protein, the enzyme goes unchecked and lung tissue is slowly destroyed, so weekly infusions raise your blood and lung levels back above the protective range. The single most important safety point is that this is a plasma product: people with IgA deficiency who carry antibodies against IgA, or who have had a severe allergic reaction to an alpha-1 product before, can react badly and should not receive it.
What does it treat?
Alpha-1-proteinase inhibitor is approved for adults with clinically evident emphysema caused by severe congenital alpha-1 antitrypsin deficiency, usually the PiZZ, PiZ(null), or null-null genotypes with blood levels below about 11 micromolar. In practice that means someone diagnosed in their thirties to fifties with shortness of breath on exertion, chronic cough, wheezing, repeat chest infections, or airflow obstruction on spirometry that looks out of proportion to their smoking history, often with emphysema at the lung bases on CT. It is sold as Prolastin-C, Prolastin-C Liquid, Zemaira, Aralast NP, and Glassia; these are considered interchangeable in dose but are not mixed in the same infusion. It is not a treatment for ordinary COPD, asthma, or bronchiectasis without the deficiency, it does not treat the liver disease that alpha-1 deficiency can also cause, and it does nothing for a sudden flare, so your inhalers, oxygen, pulmonary rehab, and vaccines all continue alongside it.
How do you take it?
It comes as a powder you mix with sterile water, or as a ready-to-use liquid, and is infused into a vein. The labeled adult dose is 60 mg per kg of body weight once every week, which for a 70 kg adult is 4,200 mg. Infusion rate depends on the brand: Prolastin-C, Prolastin-C Liquid, Zemaira, and Aralast NP run at about 0.08 mL/kg/min, which takes roughly 15 to 30 minutes, while Glassia runs slower at about 0.04 mL/kg/min over an hour or more. There is no daily ceiling because it is not a daily drug; 60 mg/kg weekly is the only dose with efficacy and safety data behind it, and larger or less frequent schedules are not established in the label. Food, timing of day, and alcohol at the time of infusion do not change how it works, and no dose change is needed for kidney or liver problems. If you miss a week, call your infusion nurse and reschedule as soon as you can rather than doubling the next dose. Stop the infusion and call your doctor if you get hives, flushing, chest tightness, wheezing, lightheadedness, or fever with chills during or right after it.
Side effects to know
- Common: Most people tolerate the infusion well, and the effects that do show up are usually mild and short-lived: headache, tiredness, dizziness, sore throat or cold symptoms, nausea, mild fever, joint aches, or redness and soreness where the IV goes in.
- Serious: Stop the infusion and get help right away for signs of a severe allergic reaction: hives or widespread rash, swelling of the lips, tongue, or throat, wheezing or trouble breathing, a racing heart, or feeling faint. Rarely people develop a delayed reaction hours later with fever, chills, and body aches, or a drop in blood pressure during the infusion, and either one means the next dose needs to be reviewed before it is given.
Who should not take it?
Do not use it if you have IgA deficiency with known antibodies against IgA, or if you have had a severe hypersensitivity reaction to any alpha-1-proteinase inhibitor product, since these products contain trace IgA. Tell your doctor first if you have heart failure, kidney disease, or another reason you cannot handle extra fluid volume, because each infusion adds a sodium and fluid load. Because it is made from pooled human plasma, screening and viral inactivation reduce but do not fully remove the risk of transmitting an infectious agent, so labels advise hepatitis A and hepatitis B vaccination before starting. No formal drug interaction studies exist, and no medicine is known to block it, but it does not replace your bronchodilators or inhaled steroids and should not be mixed with other drugs or solutions in the same line. There are no adequate studies in pregnancy or breastfeeding, so it is used only if the benefit to you clearly justifies continuing; tell your clinician if you are pregnant, planning pregnancy, or nursing. Alcohol does not interact with the infusion itself, but alpha-1 deficiency can damage the liver, so keeping intake low or at zero is the usual advice. Smoking accelerates the lung damage this drug is meant to slow, and quitting matters more than any dose adjustment.
When is it an emergency?
Call 911 if you collapse, have trouble breathing or swallowing, your face, lips, or tongue swell, your chest tightens, or your heart races and you feel faint during or after an infusion; that is anaphylaxis and it needs epinephrine, not a phone triage. Call 911 as well for sudden one-sided chest pain with breathlessness, which in emphysema can mean a collapsed lung, or for coughing up blood. Call Poison Control at 1-800-222-1222 if too much was infused or a dose was given wrong, and watch for shortness of breath at rest, swelling of the legs, or a sudden jump in weight, which point to fluid overload. Fever above 100.4 F with chills in the day or two after an infusion, or new jaundice, dark urine, or right upper belly pain, should be reported the same day rather than waited out.
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Common questions
What is the maximum dose of alpha-1-proteinase inhibitor?
The labeled dose is 60 mg per kg of body weight given into a vein once a week, and that is also the ceiling supported by evidence. For an adult weighing 70 kg that works out to about 4,200 mg per infusion. Higher weekly doses and double doses every two weeks have been tried in research settings, but neither efficacy nor safety at those doses is established in the FDA labeling. Your dose is recalculated if your weight changes meaningfully, so tell your infusion team about significant weight gain or loss.
Can I drink alcohol while on this treatment?
Alcohol does not interact with the infusion or change how the protein works. The reason clinicians still ask about it is that alpha-1 antitrypsin deficiency can damage the liver as well as the lungs, and alcohol adds to that damage. If you have any sign of liver involvement, such as abnormal liver enzymes or scarring on imaging, the usual advice is to stop drinking entirely. If your liver is normal, keep intake low and mention your actual weekly amount so it can be tracked against your liver tests.
Is it safe during pregnancy or breastfeeding?
There are no adequate, well controlled studies in pregnant or nursing people, so the labels say it should be used only if the potential benefit justifies the potential risk. Alpha-1 antitrypsin is a normal human protein and levels rise naturally in pregnancy, which is one reason some clinicians pause therapy while others continue it. The decision usually comes down to how advanced your lung disease is and how fast your lung function has been declining. Tell your pulmonologist as soon as you are pregnant or planning to be, so the plan is made before the next infusion rather than after.
Do I need to eat before an infusion, or avoid any foods?
There are no food restrictions. Because the drug goes straight into a vein, food does not affect absorption, timing, or dose. Eating something beforehand and drinking water is still a practical idea, since it makes veins easier to access and reduces lightheadedness during the infusion. If you take other medicines by mouth, keep your normal schedule on infusion days.
What are the signs of getting too much?
Overdose is uncommon because the dose is weight based and given by trained staff, and no specific toxic level has been established. The main concern with too much volume infused too fast is fluid overload: new shortness of breath at rest, swelling in the ankles or legs, a sudden weight gain over a day or two, or a pounding heartbeat. Infusing faster than the labeled rate can also cause flushing, chest tightness, or a drop in blood pressure. Call Poison Control at 1-800-222-1222 if a wrong amount was given, and call 911 if breathing becomes difficult.
Does it interact with my inhalers, antibiotics, or vaccines?
No formal drug interaction studies have been done, and no medicine is known to reduce its effect. You keep taking your bronchodilators, inhaled steroids, antibiotics, and oxygen as prescribed, because augmentation therapy slows tissue damage over years and does nothing for day to day symptoms or flares. The product must not be mixed with other drugs or diluting solutions in the same IV line or bag. Vaccines are encouraged rather than avoided, and hepatitis A and hepatitis B vaccination is specifically recommended before starting a plasma-derived product.