Pharm drugs limitations and uses

Diazepam uses

Status epilepticus → drug of choice IV

Premed, muscle relaxant, appetite stimulant in cats

Diazepam limitations

NOT for chronic epilepsy (tolerance), fatal hepatotoxicity in cats with long-term use, avoid in liver disease

Phenobarbitone uses

Drug of choice for long-term epilepsy control (dogs, cats)

Phenobarbitone limitations

Hepatotoxicity, sedation, drug interactions (enzyme inducer), requires blood monitoring

Pentobarbitone uses

Refractory status epilepticus, euthanasia agent

Pentobarbitone limitations

Profound respiratory/cardiac depression, essentially induces coma, NOT routine anticonvulsant

Potassium bromide uses

Adjunct or monotherapy for epilepsy (dogs)

Potassium bromide limitations

CANNOT use in cats (fatal lung disease), very long half-life → slow onset/adjustment

Imepitoin uses

Idiopathic epilepsy in dogs, noise phobia (labelled)

Imepitoin limitations

NOT for cats, less potent than phenobarb, sedation/ataxia possible

Propofol uses

Status epilepticus (CRI), induction anaesthetic

Propofol limitations

MUST be IV, dose-dependent apnoea/hypotension, impractical for long-term GP use

Gabapentin uses

Neuropathic pain (drug of choice), adjunct for refractory seizures

Gabapentin limitations

Poor anticonvulsant efficacy, sedation/ataxia at high doses

Levetiracetam uses

Add-on or monotherapy for epilepsy (safe in liver disease)

Levetiracetam limitations

Expensive, short half-life → frequent dosing, mild sedation/GI signs

Tricyclic antidepressants - Clomipramine/Amitriptyline uses

Separation anxiety (dogs, drug of choice TCA), FLUTD/inappropriate urination (cats)

Tricyclic antidepressants - Clomipramine/Amitriptyline limitations:

Contraindicated in cardiac disease/seizures, anticholinergic effects

SSRIs - Fluoxetine uses

Separation anxiety, compulsive behaviours, spraying in cats

SSRIs - Fluoxetine limitations

Takes 4-6 wks for effect, risk of serotonin syndrome, avoid in liver disease

Progestagens (MPA/MGA) uses

Suppress oestrus, last-line for behaviour suppression

Progestagens (MPA/MGA) limitations

Risk of pyometra, diabetes, mammary tumours — avoid in entire females & cats

Haloperidol uses

Stereotypic behaviour in horses, birds (rare)

Haloperidol limitations

ONLY used in horses/birds, extrapyramidal signs, NOT for epilepsy

Propentofylline uses

Cognitive dysfunction in dogs

Propentofylline limitations

Mild effect only, GI upset

Diazepam (behaviour) uses

Situational anxiety, appetite stimulant

Diazepam (behaviour) limitations

Hepatotoxic in cats long-term, paradoxical aggression possible

Imepitoin (behaviour) uses

Noise phobia in dogs, off-label general anxiety

Imepitoin (behaviour) limitations

NOT for cats, may cause ataxia/hyperactivity

Trazodone uses

Situational anxiety (vet visits, hospital), adjunct to SSRIs/TCAs

Trazodone limitations

Sedation, avoid in severe cardiac disease, risk of serotonin syndrom

Prednisolone uses

Drug of choice for chronic anti-inflammatory therapy, autoimmune disease, Addison's replacement

Prednisolone limitations

PU/PD/PP, immunosuppression, NEVER with NSAIDs

Dexamethasone uses

Emergency anti-inflammatory (shock, CNS oedema), induction of parturition

Dexamethasone limitations

DO NOT use in pregnancy (except induction), laminitis in horses

Triamcinolone uses

Intra-articular equine OA, systemic when pred inadequate

Triamcinolone limitations

Risk of laminitis, joint cartilage degeneration, avoid in ponies

Methylprednisolone acetate uses

Long-acting depot for chronic pruritus, feline asthma

Methylprednisolone acetate limitations

NEVER IV (suspension), long duration → adverse effects irreversible, diabetes in cats

Hydrocortisone acetate uses

Topical skin/ear/eye inflammation

Hydrocortisone acetate limitations

Weakest potency, avoid on infected/deep wounds

Hydrocortisone aceponate uses

Topical spray for canine atopic dermatitis

Hydrocortisone aceponate limitations

Local irritation/alopecia, DO NOT use in pregnancy or eyes

Frusemide uses

Drug of choice for pulmonary oedema/CHF, hypercalcaemia, hyperkalaemia

Frusemide limitations

Causes dehydration, hypokalaemia; NOT monotherapy

ACE inhibitors (Enalapril, Benazepril) uses

CHF maintenance (drug of choice vasodilator), proteinuric CKD

ACE inhibitors limitations

Contraindicated in dehydration/acute renal failure, avoid in pregnancy

Pimobendan uses

Drug of choice for canine CHF (valvular disease, DCM), preclinical mitral disease

Pimobendan limitations

Avoid in obstructive cardiomyopathy (HCM cats), rare arrhythmias

Beta-blockers (Atenolol, Propranolol) uses

HCM in cats, tachyarrhythmias, hyperthyroidism adjunct

Beta-blockers limitations

DO NOT use in acute CHF (negative inotrope), propranolol contraindicated in asthma

Digoxin uses

CHF with atrial fibrillation (rate control), +ve inotrope adjunct

Digoxin limitations

VERY narrow therapeutic index, risk of arrhythmias esp. with hypokalaemia

Ca channel blockers (Diltiazem) uses

Feline HCM - improves diastolic filling, supraventricular arrhythmias

Ca channel blockers (Diltiazem) limitations

Bradycardia, hypotension

Ca channel blockers (Amlodipine) uses

Drug of choice for feline systemic hypertension

Ca channel blockers (Amlodipine) limitations

Hypotension, reflex tachycardia

Meloxicam uses

Drug of choice NSAID in cats (low dose), OA pain, post-op analgesia

Meloxicam limitations

GI ulceration, renal injury, avoid dehydration or concurrent NSAIDs/steroids

Firocoxib uses

OA pain in dogs, musculoskeletal pain in horses

Firocoxib limitations

NOT for cats, expensive

Carprofen uses

OA and perioperative pain in dogs

Carprofen limitations

Idiosyncratic hepatopathy in dogs

Aspirin uses

Antithrombotic (saddle thrombus cats, heart disease dogs), mild analgesia

Aspirin limitations

LONG half-life in cats → toxicity, GI bleeding, irreversible platelet inhibition

Piroxicam uses

Adjunct treatment of transitional cell carcinoma, OA pain

Piroxicam limitations

High GI ulcer risk, renal toxicity

Flunixin meglumine uses

Drug of choice for equine colic pain, cattle respiratory/mastitis

Flunixin meglumine limitations

NEVER IM (tissue necrosis), right dorsal colitis in horses

Tolfenamic acid uses

Pain/fever in dogs, cats, cattle

Tolfenamic acid limitations

Renal injury in cats, limited to short-term use

Phenylbutazone uses

Drug of choice for equine musculoskeletal pain

Phenylbutazone limitations

BANNED in food animals, colitis/GI ulceration

Mavacoxib uses

Monthly OA management in dogs

Mavacoxib limitations

EXTREMELY long half-life → cannot stop if adverse effects

Grapiprant uses

OA in dogs when NSAIDs contraindicated (safer GI/renal profile)

Grapiprant limitations

Less effective than NSAIDs, mild GI upset

Fentanyl uses

Severe pain (CRI, patch, perioperative)

Fentanyl limitations

Profound respiratory depression, unreliable patch absorption

Morphine uses

Severe pain (dogs, horses), perioperative analgesia

Morphine limitations

Emesis, histamine release (DO NOT rapid IV), dysphoria in cats/horses

Methadone uses

Strong analgesia (drug of choice if morphine poorly tolerated), perioperative, neuropathic pain

Methadone limitations

Sedation, respiratory depression, serotonin syndrome risk with SSRIs

Codeine uses

Antitussive (dogs), weak analgesia

Codeine limitations

Poor analgesia in dogs, NEVER paracetamol/codeine in cats (toxic)

Butorphanol uses

Sedation/premed in dogs, cats, horses; analgesia in birds

Butorphanol limitations

Weak analgesic in mammals, short DOA, NOT for severe pain

Buprenorphine uses

Moderate pain (drug of choice opioid in cats), long DOA, multimodal analgesia

Buprenorphine limitations

Ceiling effect, expensive, mild dysphoria possible

Acepromazine uses

Premed, sedation, antiemetic (motion sickness)

Acepromazine limitations

NO analgesia, hypotension, contraindicated in boxers, stallions, shock

Droperidol uses

Pre-anaesthetic tranquilliser (with opioids)

Droperidol limitations

NO analgesia, extrapyramidal signs, avoid in seizure patients

Azaperone uses

Pig tranquilliser (aggression, transport, farrowing)

Azaperone limitations

ONLY in pigs, IM only, penile prolapse, hypotension

Xylazine uses

Sedation + analgesia (esp. LA), emetic in cats

Xylazine limitations

Profound CVS depression, cattle 10× more sensitive, abortion risk

Medetomidine uses

Sedation/analgesia in dogs & cats (minor procedures)

Medetomidine limitations

CVS depression, vomiting, avoid in heart disease/shock