Applies to antivenin (crotalidae) polyvalent: intravenous powder for solution.

Serious side effects

Along with its needed effects, antivenin (crotalidae) polyvalent may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur while taking antivenin (crotalidae) polyvalent:

Less common

• Bruising
• cough
• difficulty in moving
• difficulty swallowing
• dizziness
• fast heartbeat
• feeling of discomfort
• fever
• hives, itching, skin rash
• joint pain or swelling
• large, flat, blue or purplish patches in the skin
• muscle cramps, pain, or stiffness
• problems with bleeding or clotting
• puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
• swollen lymph glands
• tightness in the chest
• unusual tiredness or weakness

Rare

• Blurred vision
• chest pain or discomfort
• confusion
• difficulty breathing
• dizziness, faintness, or lightheadedness when getting up suddenly from a lying or sitting position
• fast, pounding, or irregular heartbeat or pulse
• large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or genitals
• noisy breathing
• rapid, shallow breathing
• sweating

Incidence not known

• Black, tarry stools
• bleeding gums
• blood in the urine or stools
• itching, swelling, redness, tenderness, or hard lump at the injection site
• pinpoint red spots on the skin
• tremor
• unusual bleeding or bruising

Other side effects

Some side effects of antivenin (crotalidae) polyvalent may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common

• Back pain
• loss of appetite
• nausea
• nervousness
• small lumps under the skin
• weight loss

Rare

• Bone pain
• feeling cold
• headache

For Healthcare Professionals

Applies to antivenin (crotalidae) polyvalent: injectable solution, intravenous powder for injection.

General

The most common adverse events were urticaria and rash.

Dermatologic

Very common (10% or more): Urticaria (16%), rash (11%)

Common (1% to 10%): Pruritus, cellulitis, subcutaneous nodule, ecchymosis

Postmarketing reports: Erythema, hyperhidrosis, angioedema

Hypersensitivity

Allergic reaction consisted of urticaria, dyspnea, and wheezing. Serum sickness included urticaria, cough, rash, pruritus, and urticaria. Acute allergic reactions manifested as anxiety, bronchospasm, chills, edema, fever, hypotension, pruritus, rash, urticaria, voice alteration, and/or wheezing.^[Ref]

Common (1% to 10%): Allergic reaction, serum sickness

Postmarketing reports: Acute allergic reactions including anaphylaxis or anaphylactoid reactions, delayed allergic reaction.^[Ref]

Hematologic

Common (1% to 10%): Coagulation disorder

Postmarketing reports: Delayed or recurrent coagulopathy or thrombocytopenia, thrombocytopenia refractory to treatment, bleeding

Cardiovascular

Common (1% to 10%): Hypotension

Postmarketing reports: Tachycardia

Nervous system

Common (1% to 10%): General paresthesia, nervousness

Postmarketing reports: Tremor, dizziness, headache^[Ref]

Respiratory

Common (1% to 10%): Asthma, cough, increased sputum

Postmarketing reports: Tachypnea, bronchospasm, wheezing, tracheal edema, dyspnea

Musculoskeletal

Common (1% to 10%): Back pain, myalgia

Postmarketing reports: Musculoskeletal chest pain, chills

Gastrointestinal

Common (1% to 10%): Nausea, anorexia, circumoral paresthesia

Postmarketing reports: Tongue swelling, lip swelling

Other

Common (1% to 10%): Chest pain, wound infection, chills

Postmarketing reports: Failure to achieve initial control, recurrent swelling refractory to treatment, prolonged hospitalization, treatment failure resulting in death, chest discomfort, swelling

Psychiatric

Common (1% to 10%): Nervousness

Ocular

Postmarketing reports: Worsening eye sight