Valproic acid (Depakote) is sometimes used in dogs. Suggested dosage ranges from 7.5-100 mg/kg. Another study reported no effect at 90mg/kg. This is approximately 4000mg for a 45kg (100lb) dog. The 2000mg (4 x 500 mg) dose should not have toxic effects even if one dog ate all 4 pills.
Sertraline (Zoloft) is sometimes used in dogs at a dose of 1-2 mg/kg/day. This would be 45-90 mg for a 45 kg dog. The 100 mg (4 x 25 mg) tablets that may have been eaten by one of your dogs should not be toxic as a one time dose.
It is unlikely that the medication individually would cause serious toxicity in your Danes. I do not have information on immediate toxicity if these drugs are taken together or effects of alcohol with these drugs.
The pills should already be out of the stomach and absorbed 4 hours after being eaten making it too late to induce vomiting.
If the dogs are not showing signs, I would not expect them to become symptomatic. If you have concerns about how the dogs are acting, call your vet or the National Animal Poison Control Center(NNN) NNN-NNNN, which has the best info on toxicity of human drugs in animals. Be aware that there is a charge for use of this service.
Let me know if you have follow up questions.