How Pharmacies Detect Prescription Drug Fraud

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By Vikas Bajaj, Attorney at Law · Last reviewed: November 1, 2026

Prescription drug misuse, especially of opioids, has been a serious public health problem in the United States for years. Because many people get these medications through a pharmacy counter, pharmacists are often the first to notice a forged or suspicious prescription. This article explains how pharmacies detect prescription drug fraud, the laws that apply in California and federally, and what to do if you are accused. Under federal rules, a pharmacist who fills a controlled-substance prescription carries “a corresponding responsibility” for whether it was issued “for a legitimate medical purpose” (21 C.F.R. § 1306.04(a)).

What is prescription drug fraud?

Prescription fraud happens when someone obtains medication, or a prescription for it, through deception. It can take the form of forged or altered prescriptions; “doctor shopping,” which means visiting several doctors to get multiple prescriptions for the same kind of drug without telling them about the others; or medical providers who write prescriptions that serve no legitimate medical purpose. California law covers both the lie and the omission: no one may obtain controlled substances or a prescription “by fraud, deceit, misrepresentation, or subterfuge” or “by the concealment of a material fact” (Health and Safety Code § 11173(a)).

The laws behind prescription fraud charges

California law

  • Health and Safety Code 11173: section 11173 prohibits obtaining, or trying to obtain, controlled substances or a prescription for them by fraud, deceit, misrepresentation or subterfuge, or by concealing a material fact. It also prohibits false statements in prescriptions and records, falsely claiming to be a doctor, pharmacist or other authorized person to obtain controlled substances, and putting a false label on a container.
  • Health and Safety Code 11368: forging or altering a prescription for a narcotic drug, passing a forged or altered prescription, or getting or possessing a narcotic drug through one is punishable by six months to one year in county jail, or by state prison (section 11368).
  • Medi-Cal fraud: when a fraudulent prescription is billed to Medi-Cal, prosecutors may also charge Welfare and Institutions Code 14107, which carries “two, three, or five years” in custody. See our guide to Medi-Cal fraud laws.

Federal law

  • 21 U.S.C. § 843(a)(3): it is a federal crime to knowingly or intentionally acquire or obtain possession of a controlled substance by misrepresentation, fraud, forgery, deception or subterfuge. The maximum penalty for a first offense is “not more than 4 years” (§ 843(d)(1)).
  • 21 C.F.R. § 1306.04(a): a valid controlled-substance prescription must be issued for a legitimate medical purpose by a practitioner acting in the usual course of professional practice. The prescriber is responsible for this, but the pharmacist who fills the prescription has a “corresponding responsibility.” That rule is why pharmacists screen prescriptions instead of simply filling them.
  • 18 U.S.C. § 1347: schemes that bill Medicare, Medi-Cal or private insurers for medically unnecessary or fraudulent prescriptions can be charged as health care fraud, with up to 10 years in prison, more if serious bodily injury or death results.

Cases involving clinics, multiple prescribers or large quantities are often investigated by federal agencies and charged in federal court, where district courts have “original jurisdiction … of all offenses against the laws of the United States” (18 U.S.C. § 3231).

How pharmacies detect prescription fraud

Prescription monitoring: CURES

California’s Department of Justice maintains CURES, the Controlled Substance Utilization Review and Evaluation System, under Health and Safety Code section 11165. For each Schedule II through V controlled substance prescription, the dispensing pharmacy must report information including the patient, the prescriber, the drug, the quantity and the dates, no later than one working day after the drug is released to the patient. Prescribers and pharmacists can use CURES to see a patient’s controlled-substance history, which makes doctor shopping and overlapping prescriptions much easier to spot. CURES data can also be provided to law enforcement and regulators, and the law sets rules on when a warrant, subpoena or court order is needed.

Patients

One warning sign pharmacists watch for is the type of medication involved. Opioid pain relievers, sedatives such as benzodiazepines, and stimulants are commonly misused. Multiple prescriptions for the same kind of drug from several doctors suggest doctor shopping. A pharmacist may also notice a patient filling prescriptions at many pharmacies far from home, running out of medication faster than prescribed, or repeatedly asking for early refills. Every Schedule II through V fill is reported to CURES “not more than one working day after the date a controlled substance is released to the patient” (Health and Safety Code § 11165(d)), so these patterns surface quickly.

Pharmacists also look for forged prescriptions. Sometimes prescription pads are stolen from a doctor’s office and used to write prescriptions for real or fake patients. Some people alter a legitimate prescription to increase the dose or quantity, or list their own or an accomplice’s phone number as the prescriber’s callback number. Forging or altering a prescription for a narcotic drug, or obtaining one with it, is punishable by “not less than six months nor more than one year” in county jail, “or in the state prison” (Health and Safety Code § 11368).

Common warning signs of a forged or altered paper prescription include:

  • The prescription looks too perfect or is more legible than is typical for the prescriber (a possible forgery under § 11368)
  • The dosages, quantities or directions are not standard
  • The directions are fully written out without the usual abbreviations
  • The prescription appears to be photocopied
  • More than one type of ink or more than one style of handwriting (a possible alteration under § 11368)
  • Combinations of drugs that would not normally be prescribed together
  • Prescriptions in the names of several different people presented by one person (possible concealment under § 11173(a))

Doctors

Prescribers can also be involved in fraud by writing unnecessary or fraudulent prescriptions. Pharmacists look for doctors who prescribe unusually large volumes of opioids, sedatives or stimulants, especially to patients without a diagnosis consistent with the drugs or amounts prescribed. Many new patients arriving at once with similar prescriptions for addictive drugs from the same doctor is another red flag. A prescription “issued not in the usual course of professional treatment” is not a valid prescription under 21 C.F.R. § 1306.04(a).

What pharmacists do when something looks wrong

A pharmacist who doubts a prescription may refuse to fill it, call the prescriber to verify it, ask for the patient’s identification, check CURES, and in some cases contact police. Pharmacists are expected to know their regular prescribers, check prescriber registration numbers, and look at prescription dates. A prescription that has gone unfilled for an unusually long time may also draw attention. Pharmacists screen because of the corresponding responsibility in 21 C.F.R. § 1306.04(a), and they can check the patient’s history in CURES under § 11165.

Why doctor shopping can be a crime

Seeing more than one doctor is not illegal. The legal problem arises when a patient hides material facts to get controlled substances, for example by not telling a doctor about an existing prescription for the same kind of drug from another provider. Health and Safety Code 11173(a) covers obtaining a prescription “by the concealment of a material fact,” not just by outright lies. Whether a particular omission was material, and whether the patient acted with the required intent, are often the central questions in these cases.

What happens after a pharmacy flags a prescription

A flagged prescription does not always lead to charges. Some situations are resolved with a call to the prescriber. Others are referred to local police, the California Department of Justice, the state licensing boards or federal agencies. Investigations of prescribers and clinics can be lengthy and often begin with requests for records, CURES data and billing information. Patients, pharmacy staff and office employees may be contacted as witnesses. If you receive a subpoena or a call from an investigator, talk with a lawyer before you respond. CURES data may be provided to public agencies “for disciplinary, civil, or criminal purposes” (§ 11165(c)(2)(A)).

For licensed professionals, a criminal investigation may run alongside licensing board proceedings or federal program actions. A conviction for a felony related to health care fraud or controlled substances can lead to mandatory exclusion from federal health care programs under 42 U.S.C. § 1320a-7(a), which can end a career in medicine or pharmacy even apart from any sentence.

If you are accused of prescription fraud

A call from a pharmacy, a visit from investigators or an arrest at the counter can happen quickly. Do not explain or argue with the pharmacist or police, and do not try to fill the prescription elsewhere. Ask for a lawyer; the Fifth Amendment lets you decline questions. Possible defenses can include a valid prescription that was misread, a prescriber who actually authorized the medication, lack of knowledge that a prescription was forged, and problems with how evidence was gathered. Patients struggling with addiction may also have treatment-based options in some cases. Learn more about our drug crimes defense work.

Frequently asked questions

Can a pharmacist refuse to fill my prescription?

Yes. Because of the corresponding responsibility under 21 C.F.R. § 1306.04(a), a pharmacist who has reason to doubt that a controlled-substance prescription is legitimate can decline to fill it. A refusal is not a criminal charge.

Is it a crime to possess medication prescribed to someone else?

It can be. Controlled substances generally may be possessed only with a valid prescription issued to you. The specific charge depends on the drug, the amount and the circumstances, so get legal advice about your situation.

Can a pharmacy share my records with police?

CURES data may be provided to law enforcement agencies for criminal purposes, subject to state rules on when a warrant, subpoena or court order is needed. Pharmacy records can also be sought by subpoena or warrant.

Vikas Bajaj has practiced criminal defense in California since 2001, including state and federal drug and health care fraud cases. Contact the Law Office of Vikas Bajaj, APC to schedule a consultation.

This article provides general information about the law and is not legal advice. Reading it does not create an attorney-client relationship. Every case depends on its own facts, so consult a lawyer about your specific situation.