C1 inhibitor

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1. any substance that interferes with a chemical reaction, growth, or other biologic activity.
2. a chemical substance that inhibits or checks the action of a tissue organizer or the growth of microorganisms.
3. an effector that reduces the catalytic activity of an enzyme.
ACE i's (angiotensin-converting enzyme i's) see angiotensin-converting enzyme inhibitors.
angiogenesis inhibitor a group of drugs that prevent growth of new blood vessels into a solid tumor.
aromatase i's a class of drugs that inhibit aromatase activity and thus block production of estrogens; used to treat breast cancer and endometriosis.
C1 inhibitor (C1 INH) a member of the serpin group, an inhibitor of C1, the initial component activated in the classical complement pathway. Deficiency of or defect in the protein causes hereditary angioedema.
carbonic anhydrase inhibitor an agent that inhibits the enzyme carbonic anhydrase; used in treatment of glaucoma and sometimes for epilepsy, familial periodic paralysis, acute mountain sickness, and kidney stones of uric acid.
cholinesterase inhibitor anticholinesterase.
COX-2 i's (cyclooxygenase-2 i's) a group of nonsteroidal antiinflammatory drugs that act by inhibiting cyclooxygenase-2 activity; they have fewer gastrointestinal side effects than other NSAIDs. Two members of the group are celecoxib and rofecoxib.
gastric acid pump inhibitor an agent that inhibits gastric acid secretion by blocking the action of H+,K+-ATPase at the secretory surface of gastric parietal cells; called also proton pump i.
HIV protease inhibitor any of a group of antiretroviral drugs active against the human immunodeficiency virus; they prevent protease-mediated cleavage of viral polyproteins, causing production of immature viral particles that are noninfective. Examples include indinavir sulfate, nelfinavir mesylate, ritonavir, and saquinavir.
HMG-CoA reductase i's a group of drugs that competitively inhibit the enzyme that catalyzes the rate-limiting step in cholesterol biosynthesis, and are used to lower plasma lipoprotein levels in the treatment of hyperlipoproteinemia. Called also statins.
membrane inhibitor of reactive lysis (MIRL) protectin.
monoamine oxidase inhibitor any of a group of drugs that inhibit the action of monoamine oxidase, the enzyme that breaks down norepinephrine and serotonin, prescribed for their antidepressant action; the most widely used ones are isocarboxazid, phenelzine, and tranylcypromine. They are also used in the prevention of migraine.
α2-plasmin inhibitor α2-antiplasmin.
plasminogen activator inhibitor (PAI) any of several regulators of the fibrinolytic system that act by binding to and inhibiting free plasminogen activator. Their concentration in plasma is normally low, but is altered in some disturbances of bodily hemostasis. PAI-1 is an important fast-reacting inhibitor of t-plasminogen activator and u-plasminogen activator. Its synthesis, activity, and release are highly regulated; elevated levels of it have been described in a number of disease states. PAI-2 is a normally minor inhibitor that greatly increases in concentration during pregnancy and in certain disorders. PAI-3 is protein C inhibitor.
platelet inhibitor any of a group of agents that inhibit the clotting activity of platelets; the most common ones are aspirin and dipyridamole. See also antiplatelet therapy.
protease inhibitor
1. a substance that blocks activity of endopeptidase (protease), such as in a virus.
protein C inhibitor the primary inhibitor of activated anticoagulant protein C; it is a glycoprotein of the serpin family of proteinase inhibitors and also inhibits several other proteins involved in coagulation (thrombin, kallikrein, and coagulation factors X and XI) and urokinase. Called also plasminogen activator inhibitor 3.
proton pump inhibitor gastric acid pump i.
reverse transcriptase inhibitor a substance that blocks activity of the reverse transcriptase of a retrovirus and is used as an antiretroviral agent. Some are nucleosides or nucleoside analogues, and those that are not are therefore often called non-nucleoside reverse transcriptase inhibitors.
selective serotonin reuptake inhibitor (SSRI) any of a group of drugs that inhibit the inactivation of serotonin by blocking its absorption in the central nervous system; used as antidepressants and in the treatment of obsessive-compulsive disorder and panic disorder.
serine protease inhibitor (serine proteinase inhibitor) serpin.
topoisomerase i's a class of antineoplastic agents that interfere with the arrangement of DNA in cells.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

C1 inhibitor (human)

(See-one in-hib-i-tor) ,


(trade name)


Therapeutic: antiangioedema agents
Pharmacologic: proteinase inhibitors
Pregnancy Category: C


Routine prophylaxis against angioedema attacks in adult and adolescent patients with Hereditary Angioedema (HAE).


Replaces C1 inhibitor which is deficient in patients with HAE. C1 inhibitor is necessary in preventing the chain of events which alter vascular permability resulting in life-threatening swelling in patients with HAE.

Therapeutic effects

Decreased frequency, intensity and duration of HAE attacks.


Absorption: IV administration results in complete bioavailibility.
Distribution: Unknown.
Metabolism and Excretion: Unknown.
Half-life: Single dose—56 hr.

Time/action profile

IVwithin 1 hr12 hr3–4 days


Contraindicated in: Life-threatening immediate hypersensitivity reactions.
Use Cautiously in: Patients with known risk of thrombotic events; Obstetric / Lactation: Use during pregnancy only if clearly needed; use cautiously during lactation; Pediatric: Safety not established.

Adverse Reactions/Side Effects

Central nervous system

  • headache


  • thromboembolic events (life-threatening)


  • rash


  • Hypersensitivity reactions including anaphylaxis


Drug-Drug interaction

None noted.


Intravenous (Adults and adolescents) 1000 units every 3 or 4 days.


Powder for injections (requires reconstitution): 500 units/vial

Nursing implications

Nursing assessment

  • Assess for signs (facial or abdominal swelling, pain, nausea, vomiting, cramps, diarrhea) and frequency of HAE.
  • Assess for signs and symptoms of hypersensitivity reactions (hives, urticaria, tightness of the chest, wheezing, hypotension, anaphylaxis) during or after injection. Symptoms may be similar to HAE attacks; consider treatment methods carefully. If hypersensitivity occurs, discontinue infusion treat symptomatically. Epinephrine should be immediately available for treatment of acute severe hypersensitivity reaction.
  • Monitor patients with known risk factors for thrombotic events.

Potential Nursing Diagnoses

Ineffective airway clearance (Indications)


  • Intravenous Administration
  • Intermittent Infusion: Diluent: Reconstitute each of 2 vials with 5 mL of Sterile Water for Injection by removing the protective covering from one end of the double-ended transfer needle and inserting exposed needle through the center of the diluent vial stopper. Remove protective covering from the other end of the double-ended transfer needle. Invert diluent vial over the upright and slightly angled C1 inhibitor vial; then rapidly insert the free end of the needle through the center of the C1 inhibitor vial stopper. Vaccuum in the vial will draw in the diluent. Do not use if there is no vacuum in the vial. Disconnect the two vials by removing the needle from the C1 inhibitor vial stopper and discard the diluent vial, along with the transfer needle directly into the sharps container. Gently swirl C1 inhibitor vial until all powder is completely dissolved. Solution is colorless to slightly blue; do not administer solutions that are discolored, turbid, or contain a precipitate. Insert the filter needle into the vial of reconstituted solution. Inject air into the vial and withdraw the reconstituted C1 inhibitor into the syringe. Repeat with a second vial to make complete dose. Concentration: 100 units/mL. Discard partially used vials. Attach a suitable needle or infusion set with winged adapter, and inject intravenously. Administer at room temperature within 3 hr of reconstitution. Do not freeze; protect solution from light.
  • Rate: Administer at an initial infusion rate 1 mL/min over 10 min. If tolerated, continue same as the maintenance infusion rate.
  • Y-Site Incompatibility: Do not mix with other materials.

Patient/Family Teaching

  • Inform patient that C1 inhibitor is made from human plasma and may contain infectious agents that can cause disease.
  • Instruct patient to notify health care professional immediately if signs and symptoms of allergic hypersensitivity reactions or thrombosis (new onset swelling and pain in limbs or abdomen, new onset chest pain, shortness of breath, loss of sensation or motor power, altered consciousness or speech) occur.
  • Advise female patients to notify if health care professional if pregnancy is planned or suspected or if breastfeeding.

Evaluation/Desired Outcomes

  • Decreased frequency, intensity and duration of HAE attacks.
Drug Guide, © 2015 Farlex and Partners
References in periodicals archive ?
M2 PHARMA-May 29, 2019-KalVista Pharmaceuticals Presents KVD900 Data at C1-Inhibitor Deficiency and Angioedema Workshop
Hereditary and acquired C1-inhibitor deficiency: biological and clinical characteristics in 235 patients.
This is the case in most developed countries with good healthcare access and registered effective treatments such as purified C1-inhibitor concentrate or bradykinin-[beta]2-receptor antagonists.
A quantitative and functional analysis of C1-inhibitor, as well as C1q level, were within the normal ranges.
Farkas, "The natural history of hereditary angioedema and the impact of treatment with human C1-inhibitor concentrate during pregnancy: A long-term survey," European Journal of Obstetrics & Gynecology and Reproductive Biology, vol.
C1s-binding activity of C1-INH was assessed using the MicroVue[TM] C1-Inhibitor Plus EIA (Quidel Corporation, CA, USA), according to the manufacturer's procedure.
Strong correlation of high EBNA-1-lgG levels with edematous attacks Involving upper airway mucosa in hereditary angioedema due to C1-inhibitor deficiency.
HAE is caused by a deficiency of the C1 esterase inhibitor protein and because defective C1-Inhibitor does not perform its regulatory function, a biochemical imbalance can occur and produce unwanted peptides that induce the capillaries to release fluids into surrounding tissue, causing swelling or edema concluded the company.
Casein kinase II alpha subunit and C1-inhibitor are independent predictors of outcome in patients with squamous cell carcinoma of the lung.
Laboratory tests Result % of cohort Complement C1-inhibitor tests Normal 72.4% Not tested 27.6% Negative 55.2% HR test chronic urticaria Not tested 40.0% Positive 2.9% Data missing 1.9% Increased C-reactive protein Range 7-126 (normal < 6 mg/L) 14.3% Leukocytosis More than 8.8 x [10.sup.9]/L 15.2% Tryptase More than 12 ng/mL 5.7% Table 6: Multivariate logistic regression analysis.