Drug Monograph
Full clinical overview, indications, dosage references & safety notes.
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Berenil RTUGanasegVeriben
Overview
Diminazene (Berenil® RTU) is an antiprotozoal agent used in veterinary medicine primarily for the treatment of protozoal infections in dogs and cats, including babesiosis and cytauxzoonosis. It is typically administered as a single intramuscular injection, although repeat dosing may be required in certain cases, with increased risk of toxicity.
The drug is rapidly absorbed after intramuscular administration and distributes widely in the body, with high concentrations in organs such as the liver and kidneys. It may also penetrate the central nervous system to a limited extent. Elimination is variable between species, with dogs showing wide variability and cats having a relatively short elimination half-life.
Mechanism of Action (MOA): The exact mechanism of action of diminazene is not fully understood. In protozoal infections such as Babesia spp., it is believed to interfere with aerobic glycolysis and inhibit DNA synthesis, leading to impaired parasite survival. The drug may not completely eliminate the organism but can suppress clinical signs for an extended period due to its persistence in tissues.
Indications
Diminazene is used in dogs and cats for the treatment of selected protozoal infections. Its use is typically extra-label in small animal practice and should be guided by disease severity, organism involved, and clinical response.
- Babesiosis (dogs): Used for treatment of large Babesia infections (B. canis, B. rossi, B. vogeli) where it is generally effective. Diminazene is POORLY effective as monotherapy against small Babesia species (B. gibsoni, B. conradae) and should be combined with other agents in those cases.
- Babesia gibsoni infection (combination protocol): May be used as part of a multimodal treatment protocol. The currently recommended combination for B. gibsoni is atovaquone (13.3 mg/kg PO q8h with food) plus azithromycin (10 mg/kg PO q24h) for 10 days, with diminazene as adjunctive therapy where available; clindamycin alone is no longer considered first-line.
- Cytauxzoonosis (cats): Diminazene is NOT the preferred treatment for Cytauxzoon felis. Atovaquone (15 mg/kg PO q8h) + azithromycin (10 mg/kg PO q24h) for 10 days is the current standard of care, with reported survival rates of approximately 60%. Diminazene has variable and limited efficacy in cats and is reserved for cases where the preferred protocol is unavailable.
Dosage (Reference)
Dog
In dogs, diminazene is used for protozoal infections such as babesiosis and trypanosomiasis. Dosing protocols vary depending on the organism and clinical scenario, and response can be variable with a risk of toxicity at higher or repeated doses.
| Clinical use | Route | Dose | Frequency | Notes |
|---|---|---|---|---|
| Babesia spp. infection | IM | 3.5 mg/kg once | Single dose | Variable efficacy; CNS toxicity may occur and can be severe. |
| Babesia gibsoni (combination protocol) | IM | 3.5 mg/kg once | Single dose | For B. gibsoni: combination atovaquone (13.3 mg/kg PO q8h with food) + azithromycin (10 mg/kg PO q24h) for 10 days is the recommended protocol. Diminazene 3.5 mg/kg IM may be used as an adjunct where available. Clindamycin/imidocarb protocols have largely been replaced by the atovaquone+azithromycin combination. |
| African trypanosomiasis | IM | 3.6–7 mg/kg every 2 weeks | q2wk | Repeat dosing may be required for relapse control; increases risk of cumulative toxicity. |
• Usually administered as a single dose; repeated dosing increases risk of CNS toxicity.
• Do not repeat dosing with this or related drugs within ~6 weeks due to cumulative toxicity risk.
• Wide interpatient variability in response and pharmacokinetics may occur.
• Monitor for neurologic and systemic adverse effects after administration.
• Administer as a DEEP intramuscular injection (e.g., quadriceps or epaxial muscles). Pain on injection is expected; deep technique with adequate needle length reduces local tissue irritation and post-injection swelling.
• Confirm parasite clearance with serial PCR testing — recommended 2–3 sequentially negative PCR results at approximately 2 months post-treatment before declaring the patient parasitologically cured. Clinical resolution alone is insufficient.
• Supportive care is essential alongside antiprotozoal therapy: IV crystalloid fluids for haemolysis-induced AKI risk, blood transfusion if PCV is critically low, and analgesia as needed.
Cat
In cats, diminazene is GENERALLY NOT RECOMMENDED. Although it has been used for cytauxzoonosis and feline babesiosis, multiple studies have failed to demonstrate efficacy and severe adverse effects (ptyalism despite atropine pretreatment, persistent vomiting, hepatic enzyme elevations) are common. Atovaquone + azithromycin is the preferred protocol for Cytauxzoon felis; for B. felis, primaquine has been used with greater safety.
| Clinical use | Route | Dose | Frequency | Notes |
|---|---|---|---|---|
| Cytauxzoonosis / babesiosis | IM | 3 mg/kg IM as 2 doses 7 days apart, and 4 mg/kg IM daily for 5 days. Both protocols failed to demonstrate clinical efficacy.” | Single dose | Protocols studied include single or repeated dosing; efficacy in reducing parasite burden is variable. |
• Studied protocols include 3 mg/kg IM (2 doses 7 days apart) or higher repeated dosing regimens.
• Dose-intensified regimens (e.g., 4 mg/kg daily for several days) were associated with frequent adverse effects without clear efficacy benefit.
• Short elimination half-life compared with dogs may influence dosing considerations.
• Close monitoring for adverse effects is recommended due to variable response.
• Pretreat cats with atropine 0.02 mg/kg SC 30 minutes before diminazene injection to limit cholinergic adverse effects (ptyalism, lacrimation, defecation, vomiting). Severe ptyalism has been reported even with atropine pretreatment.
• Preferred Cytauxzoon felis protocol : atovaquone 15 mg/kg PO q8h with food + azithromycin 10 mg/kg PO q24h × 10 days, plus aggressive supportive care (IV fluids, anticoagulation, blood products). Reported survival ~60%. Diminazene should be reserved for cases where this protocol is unavailable.
• For B. felis specifically: primaquine 1 mg/kg IM as a single dose has been used with greater safety than diminazene . This is a useful alternative when diminazene is unavailable or contraindicated.
Warnings & Precautions
Diminazene use in dogs and cats requires caution due to its potential for cumulative toxicity and variable safety profile. Appropriate patient selection and careful consideration of dosing frequency are essential to minimize risks.
- Cumulative toxicity: Repeated dosing increases the risk of toxicity, particularly affecting the central nervous system; dosing intervals should be carefully considered.
- Dosing interval restriction: Repeat administration with diminazene or other related diamidine compounds should generally be avoided within a 6-week period to reduce toxicity risk.
- Neurologic risk: CNS toxicity, including severe neurologic signs, may occur in dogs, especially with higher or repeated doses.
- Use in compromised patients: Use cautiously in animals with systemic illness, as safety data are limited and adverse effects may be more pronounced.
- Reproductive safety: Safety in pregnant or nursing animals has not been established; use only when potential benefits outweigh risks.
- Milk distribution: The drug is excreted into milk; potential effects on nursing offspring are unknown.
- Camelid/donkey contraindication: Species susceptibility: camelids (camels, llamas, alpacas) and donkeys are HIGHLY susceptible to diminazene toxicity and the drug is contraindicated in these species . Relevant for mixed-practice prescribers.
- Feline neurotoxicity: Not mentioned in plumb or papich
- Hepatic enzyme elevations: Hepatic enzyme elevations have been documented in cats receiving diminazene . Consider checking baseline ALT/ALP and rechecking 7–14 days post-treatment, especially in cats and in dogs with pre-existing hepatic disease.
Drug Interactions
No clinically significant drug interactions have been identified for diminazene in veterinary patients. However, as with any antiprotozoal therapy, concurrent drug use should be evaluated on a case-by-case basis.
- No known significant interactions: Current data do not indicate any clinically relevant drug interactions in dogs or cats.
Side Effects & Overdose
Side Effects
At therapeutic doses, diminazene is generally well tolerated in dogs, although adverse effects may still occur. Most reactions are mild, but rare severe neurologic complications have been reported.
- Gastrointestinal effects: Vomiting and diarrhea may occur following administration.
- Injection site reactions: Pain and localized swelling can be observed after IM injection.
- Cardiovascular effects: Transient decreases in blood pressure may occur.
- Neurologic effects (rare): Ataxia, seizures, and severe CNS signs have been reported in a very small percentage of cases.
- Severe reactions: Death has been reported rarely, particularly in dogs.
- Cat-specific cholinergic effects: Cat-specific adverse effects : severe ptyalism (often persisting despite atropine pretreatment), persistent vomiting, lacrimation/defecation, and elevated hepatic enzymes. These cholinergic and hepatic effects are a major reason diminazene is not recommended for cats.
Overdose
Information on diminazene overdose in small animals is limited, but dogs appear to be particularly sensitive to toxic effects at higher doses.
- Toxic dose threshold (dogs): Doses above approximately 10 mg/kg IM may result in severe toxicity.
- Systemic toxicity: Overdose may cause severe gastrointestinal, respiratory, neurologic, or musculoskeletal signs.
- High-risk species sensitivity: Dogs are considered more susceptible to toxic effects compared to many other species.
- Management: No specific antidote exists; treatment is supportive based on clinical signs.
- Consultation: Veterinary poison consultation is recommended in suspected overdose cases.
Key Notes
Practical clinical considerations that can help optimize the use of diminazene in dogs and cats:
- Variable efficacy: Clinical response can be inconsistent, particularly in certain protozoal infections, so treatment success should always be confirmed with follow-up testing.
- Parasite suppression vs elimination: The drug may not completely clear the infection, and recurrence of clinical signs is possible after initial improvement.
- Role in combination therapy: Often used as part of combination protocols rather than as a sole agent, especially in difficult or resistant infections.
- Pharmacokinetic variability: Significant interpatient variability can affect both efficacy and safety, making standardized outcomes less predictable.
- CNS penetration considerations: Although penetration into the CNS is limited, it may increase in certain disease states, which can influence both therapeutic effects and risk profile.
- Follow-up monitoring: Serial laboratory testing (e.g., PCR or hematologic parameters) is important to assess treatment response and detect relapse.
- Availability limitations: Not commercially available in some regions, which may affect accessibility and clinical use decisions.
