What is the primary measure used for a medication's weight?

The primary measure used for a medication's weight is grams. In the context of pharmaceuticals and medicine, grams are commonly utilized because they provide a standardized measurement that is appropriate for the small amounts of substances typically involved in medications.

Grams allow for precise dosing, which is crucial for safety and effectiveness in medication administration, as many medications are effective at very low doses. Using grams provides clarity and prevents confusion that may arise with larger units of measurement, particularly in the context of healthcare settings where accurate dosing is critical.

Other units like kilograms and pounds are generally more suitable for measuring larger weights, but they are not as effective or practical for the tiny quantities often required in medication. While liters are a volume measurement and not directly related to weight, they may be relevant when discussing liquid medications, but that does not directly answer the question regarding weight. Thus, grams is the most appropriate unit of measurement for medications.