The four-year-old firm will now promote athlete's foot treatment Lamisil, Savlon first aid cream, skin treatment Eurax and eye care brand Vital Eyes.
Toniq said it won the accounts as part of Novartis's policy of regularly conducting agency reviews.
Novartis made headlines recently when it revealed it was working on spinal-chord repairing antibodies with the University of Zurich.
Two-strong Toniq was formed in 2002 by ex-Ruder Finn managing director Alison Miles and PR consultant Simon Greenbury.
It also works on Novartis's Nicotinell, Voltarol Emulgel P, Otrivine, Tixylix and Ex-Lax brands.