Didn't work as expected after Lysine in cats

The FDA has received 21 reports of didn't work as expected in cats after Lysine. That is 19% of all reports for this medicine, compared with 8.7% across reports for all cat medicines, so it is reported unusually often with this medicine.

21Reports

43%Marked serious

4.8%Recovered

4.8%Died or euthanised

31 daysTypical onset

How soon it started

Same day

2 13%

1–2 days

0 0.0%

3–7 days

1 6.3%

1–4 weeks

4 25%

Over a month

9 56%

How the animals did

Recovered

1 4.8%

Still unwell when reported

15 71%

Euthanised

1 4.8%

Not known

4 19%

Problems reported at the same time

Vomiting

4 19%

Loss of appetite

4 19%

Lethargy

4 19%

Liver problems

3 14%

Skin rash or irritation

3 14%

Intentional misuse

3 14%

Vocalising

2 9.5%

Weight loss

2 9.5%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Type: medicine.

Questions owners ask

Can Lysine cause didn't work as expected in cats?: 21 reports link the two, but a report alone does not prove the medicine was the cause: other illnesses, other medicines or coincidence can be involved. Your vet can judge it for your animal.
How soon after a dose was it reported?: In half of the reports with dates, it started within 31 days of the first dose.
What should I do?: Don't give another dose until you've spoken to your vet, and keep the packaging so you can tell them the product and dose. Your vet can also report it to the FDA (or you can, through the manufacturer or FDA form 1932a).

Didn't work as expected with similar medicines

Didn't work as expected after Ketamine 586 reports · 18% of its reports
Didn't work as expected after Butorphanol 220 reports · 9.8% of its reports
Didn't work as expected after Isoflurane 144 reports · 7.1% of its reports
Didn't work as expected after Tiletamine + Zolazepam 265 reports · 16% of its reports
Didn't work as expected after Methylprednisolone 227 reports · 14% of its reports
Didn't work as expected after Propofol 81 reports · 6.9% of its reports
Didn't work as expected after Atipamezole 120 reports · 12% of its reports
Didn't work as expected after Midazolam 31 reports · 4.1% of its reports
Didn't work as expected after Florfenicol + Mometasone + Terbinafine 42 reports · 6.1% of its reports
Didn't work as expected after Orbifloxacin 76 reports · 11% of its reports

All reported side effects of Lysine in cats · Medicines most reported with didn't work as expected