These products generally contain a larger dose of drug than immediate release products in a formulation that slowly releases the drug over a longer period of time. By crushing these products the release mechanism will be destroyed allowing the full dose of drug to be released as a single dose, termed "dose-dumping", and possibly leading to adverse reactions. In addition this release of a large dose can result in quicker drug absorption and metabolism, and a longer period of time between doses where drug levels can fall to sub therapeutic levels.

Where patients are stabilised on modified release products but have difficulty swallowing, they would need to be converted to an immediate release form that could be crushed. This would generally require a reduction in dose and an increase in dosage frequency.

As a general rule pharmacists should not advise patients or prescribers that it is safe or appropriate to crush modified release products. However, some capsules contain modified release pellets that can safely be released from the outer capsule shell. Examples of modified release capsules that can be opened include Zomorph, MXL, Slo-phyllin, Feospan and Episenta. It is important that pharmacists understand the release mechanism of a modified release product before advising on its suitability to be crushed or opened.

Enteric coated products

Enteric coating is designed to prevent the release of the drug in the stomach ensuring the drug is released in the small intestine. This acts to either protect the stomach from the effects of the drug or to protect the drug from the acidic environment of the stomach. Crushing of enteric coated products can result in stomach irritation and/or a reduction in efficacy.