You build up to it over weeks, allowing your body to adapt to the medication and minimizing gastrointestinal side effects
But a study earlier this year found 65% of those without diabetes discontinued the drugs in less than one year, according to a study in JAMA Network Open

Acronyms CrCl - Creatinine clearance GLP-1 - Glucagon-Like Peptide-1 P - Drugs with pediatric dosing Dulaglutide Trulicity Trulicity Dosage forms Single-dose pen 0.75 mg/0.5 ml 1.5 mg/0.5 ml 3 mg/0.5 ml 4.5 mg/0.5 ml Comes in carton with 4 pens Dosing Type 2 diabetes Starting: 0.75 mg once weekly Maintenance: 0.75 - 4.5 mg once weekly Max: 4.5 mg once weekly Increase to next higher dose if needed at intervals of 4 weeks May administer without regard to food If a dose is missed, administer ASAP if there are at least 3 days until the next scheduled dose If less than 3 days remain before the next scheduled dose, skip the missed dose and administer the next dose on the regularly scheduled day In each case, patients can then resume their regular once weekly dosing schedule The day of weekly administration can be changed if necessary as long as the last dose was administered 3 or more days before Kidney disease No dose adjustment is recommended in patients with renal impairment including end-stage renal disease Gastrointestinal side effects may be worse in patients with kidney disease Liver disease In a study of patients with varying degrees of liver disease, no clinically relevant change in dulaglutide pharmacokinetics was observed

Taking two doses close together concentrates the GI-slowing effects and dramatically increases the risk of nausea, vomiting, and other side effects
Current evidence suggests tirzepatide is not hepatotoxic and may actually benefit liver health in patients with metabolic dysfunction-associated steatotic liver disease (MASLD)
SURPASS-CVOT compared once-weekly tirzepatide with dulaglutide in adults with type 2 diabetes and high cardiovascular risk, showing a 9% relative risk reduction in MACE (HR 0.92, 95% CI 0.83 to 1.01)