Lithium
Lithium carbonate is primarily used in veterinary medicine to stimulate bone marrow production. It is indicated for the treatment of **idiopathic aplastic anaemia**, **cytotoxic drug-induced neutropenia** or **thrombocytopenia**, **oestrogen-induced bone marrow suppression**, and **cyclic haemopoiesis**. > **Clinical Warning**: There is a lag phase of up to 4 weeks before its clinical effects may be seen. Experimental studies suggest lithium may prevent neutropenia associated with cytotoxic drugs when administered concomitantly, though robust clinical trials are lacking. **Clinical Pearl**: The recommended therapeutic serum lithium concentration is 0.5-1.8 mmol/l, which should be assessed every 3 months if possible.
Mechanism: Lithium **stimulates bone marrow stem cells**, causing an increase in the production of haemopoietic cell lines → particularly **granulocytes**.
Dosing by species
- Bone marrow suppression / neutropenia · 10 mg/kg · PO · q12h · Give with food.
- Contraindicated · Do not use · PO · Lithium is toxic to cats.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Routes of administration
Contraindications
- Cats (highly toxic)
- Renal impairment
- Cardiac disease
- Conditions with sodium imbalance (e.g., hypoadrenocorticism)
- Dehydration
Adverse effects
- Nausea
- Diarrhoea
- Muscle weakness
- Fatigue
- Polyuria (PU)
- Polydipsia (PD)
- Seizures
- Hypothyroidism (blocks release of T3 and T4)
Drug interactions
- ACE inhibitors · Reduces lithium excretion, increasing the risk of toxicity · major
- Loop diuretics · Reduces lithium excretion and causes sodium depletion, worsening toxicity · major
- Thiazide diuretics · Reduces lithium excretion and causes sodium depletion, worsening toxicity · major
- NSAIDs · Reduces lithium excretion, increasing the risk of toxicity · major
- Theophylline · May increase the excretion of lithium, potentially reducing efficacy · moderate
- Neostigmine · Lithium antagonizes the effects of neostigmine · moderate
- Pyridostigmine · Lithium antagonizes the effects of pyridostigmine · moderate
- Diltiazem · Concurrent administration may result in neurotoxicity · major
- Verapamil · Concurrent administration may result in neurotoxicity · major
Monitoring
- Serum lithium concentration (target 0.5-1.8 mmol/l, assess every 3 months)
- Thyroid status (T3 and T4, assess every 6 months)
- Renal function
- Hydration status and serum sodium levels
Overdose
Lithium is **nephrotoxic at high doses**. Toxicity is significantly worsened by sodium depletion (e.g., concurrent diuretic use or dehydration). Signs of toxicity may include severe nausea, diarrhoea, muscle weakness, polyuria/polydipsia, and seizures.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.