Crotalidae Immune F (Intravenous)

Crotalidae is used for treating people who have been bitten by the North American rattlesnake.


Crotalidae Immune F (Anavip) is an anti-venom medication used for treating poisoning in people who have been bitten by the North American rattlesnake. This medication comes in the form of a lyophilized powder (powder for solution), which is then used to produce an injectable solution for administration.

Crotalidae Immune F helps resolve symptoms of poisoning, such as loss of control of muscle, trouble breathing, slurred speech, abnormal eye movements, excessive salivation, vomiting and frothing in the mouth.

You must only take this medication under the direct supervision of a healthcare professional.

Conditions treated

  • North American Rattlesnake bite

Type of medicine

  • Anti-venom

Side effects

Apart from its useful effects, this medicine may bring about some undesirable effects. While not all these effects can occur, those that do may need immediate medical attention.

Check with your nurse or doctor straight away if you experience any of the following effects:

More common:

  • Itching skin/rash
  • Difficulty with moving
  • Redness/flushing of skin
  • Muscle stiffness or pain
  • Joint pain
  • Nausea
  • Vomiting
  • Unusual weight loss or gain
  • Tingling of feet or hands
  • Unusually warm skin

Less common:

  • Black, tarry stools
  • Chills
  • Bleeding gums
  • Blood in stools or urine
  • Confusion
  • Reduced urination
  • Dry mouth
  • Fever
  • Fainting
  • Dizziness
  • Lightheadedness
  • Increased heart rate
  • Thirst
  • Sunken eyes
  • Rapid breathing
  • Red pinpoint spots on skin
  • Wrinkled skin
  • Unusual bruising or bleeding
  • Unusual weakness/tiredness

Some Crotalidae Immune F side effects may not necessitate medical care as these effects may disappear during treatment as you adapt to the medication. Your healthcare specialist may recommend ways to prevent or relieve some of these effects. However, if any of the effects below are bothersome, persist, or you have questions about them, don't hesitate to consult your doctor.

More common:

Less common:

  • Trouble sleeping
  • Nervousness or fear

Other Anavip side effects not outlined above may happen in some patients, as well. If you have other different effects, be sure to see your healthcare professional promptly.


Treatment should be started with Crotalidae Immune F as soon as you suffer poisoning from a North American rattlesnake bite.

This medication is only taken intravenously. It should be administered by a doctor or other trained healthcare provider in a clinic or hospital. The duration of treatment and the dose can vary with the seriousness of your condition.

Normal dosing routine for poisoning caused by a North American rattlesnake bite comprises 10 vials. Every vial contains sodium chloride, sucrose, glycine to act as a stabilizer and small amounts of pepsin, borates, sulfates and cresol.

Some medications may have an additional leaflet containing patient information. If you need more information about Anavip, please talk to your doctor, pharmacist, nurse or other healthcare professional.

If you suspect you or your child have suffered an Anavip overdose, get medical attention promptly or contact your poison control agency. Be ready to demonstrate or describe what was consumed, when it happened and how much was consumed.


While some medications shouldn't be taken together at all, sometimes two different medications may be taken together, even if there might be an interaction. In such cases, your healthcare professional may want to adjust your dose or give you other precautions. Be sure to report any other medications you're using (i.e. prescription and non-prescription).

Other interactions

You shouldn't take certain medicines when you are about to have a meal, nor eat certain kinds of foods as interactions can occur. Interactions may also occur if you use tobacco or alcohol with certain medicines. Discuss with your physician the use of Crotalidae Immune F with food, alcoholic drinks and cigarettes.


Before you decide to take a medication, you must weigh its risks against the positive effects it will cause. You will make this decision with your doctor. Before using Crotalidae Immune F, you should take the following into consideration.


Let your healthcare professional know if you've ever suffered any allergic or unusual reactions to this medication or any other medication. Also, let them know if you have other kinds of allergies, such as to foods, animals, dyes and preservatives. Before using non-prescription products, carefully read the ingredients on the package or label.


Relevant studies done so far haven't demonstrated problems specific to children that would restrict the efficacy of Crotalidae Immune F in kids.


Relevant studies done so far haven't shown problems specific to older adults that would affect the efficacy of Crotalidae Immune F in seniors.

Pregnancy (category C)

For Crotalidae Immune F, not enough studies in pregnant ladies have been carried out and either animal studies have demonstrated an undesirable effect of this medication or there have been no animal studies done.


There aren't enough studies done in women to determine the risk to the infant when using Crotalidae Immune F while breastfeeding. Be sure to weigh the possible risks against the possible benefits before use.

It is recommended that you visit your doctor regularly to check whether Crotalidae Immune F is working well or not.

In addition, make sure to follow the guidelines below while you're using this medication:

Severe hypersensitivity reactions, like anaphylaxis, may happen with this anti-venom treatment. While you're receiving this infusion, it is recommended that you're closely monitored for allergic reactions, as well as readiness for intravenous therapy with corticosteroids, epinephrine and diphenhydramine hydrochloride.

If you have an anaphylactic reaction while receiving this infusion, you should stop taking the anti-venom injection and seek proper emergency medical care. If you're allergic to horse protein, you are more likely to have an anaphylactic reaction.

Tell all your healthcare professionals that you take Crotalidae Immune F. This includes your physician, nurse, dentist, and pharmacist.

Let your blood work be checked as instructed by your healthcare provider. Talk about this with your doctor.

Also, you should call your doctor immediately if you suffer any unusual bleeding or bruising (such as blood in urine or stools, excessive menstrual bleeding, persistent oozing or excessive bruising from minor injuries) after hospital discharge.

In addition, serum sickness or delayed hypersensitivity reactions can also happen after discharge from hospital. Therefore, you should watch out for signs of serum sickness or delayed allergic reactions (such as vomiting, syncope, angioedema, myalgia, urticaria, and arthralgia). Treatment of these reactions is usually symptomatic and involves using corticosteroids, analgesics, anti-histamines and anti-pyretics.

Your doctor will closely monitor you or your child's progress while you're receiving Crotalidae Immune F. This will enable your doctor to determine if the medication is working well and doesn't cause any adverse effect. You may need blood tests to check for adverse effects.

Tell your physician or get medical assistance promptly if you suffer any of these signs or symptoms of a very serious side effect:

  • Signs of allergic reaction, including hives, rash, red, swollen, itching, peeling, or blistered skin with or without fever, tightness in the throat or chest, wheezing, trouble talking or breathing, swelling of throat, tongue, lips, or face, unusual hoarseness.
  • Signs of bleeding, including vomit the resembles coffee grounds or vomiting blood, blood in urine, coughing up blood, red, black, or tarry stools, abnormal vaginal bleeding, bleeding from gums, unexplained bruises or bruises that grow larger, or any severe or uncontrolled bleeding.

Horse plasma is used to make Crotalidae Immune F. Some products made from horse blood have passed viruses on to people who have used them, but the risk is negligible. Speak to your physician if you suffer symptoms that trouble you.


Since this medication is only given by a trained healthcare professional or under their direct supervision, you won't keep it at home.


Crotalidae Immune F is made from horse (equine) blood and there's a high risk of severe allergic (hypersensitivity) reactions. Additionally, certain contagious agents, like viruses, can be passed on by horse blood products in people who've received them.

While the chances of virus transmission have been significantly minimized these days due to the rigorous process involved in manufacturing, you should discuss this concern with your healthcare professional. If you're just about to begin therapy with this medication, you should carefully weigh its possible risks against the possible benefits.

Sometimes the existence of other medical conditions does affect the positive effects of Crotalidae Immune F and may even result in serious toxic effects.

If you've suffered any allergic or unusual reaction to any medication, you must let your healthcare professional know about it. In addition, be sure to inform your healthcare professional if you've had allergies to cresol and horse blood products.

Moreover, this anti-venom may result in serious kinds of hypersensitivity reactions, including anaphylaxis. This can be a life-threatening symptom that requires urgent medical attention. Therefore, make sure to consult your physician if you've developed these symptoms after taking Crotalidae Immune F:

  • style="font-weight: 400;">Difficulty in swallowing
  • Hoarseness of voice
  • Rashes
  • Itching
  • Respiratory distress
  • Edema