CORDY, J.

On December 10, 2001, Robert D. Riskind suffered a grand mal seizure while driving home from work, causing him to lose control of his vehicle and strike the plaintiff, Richard Medina, as he was exiting his motor vehicle (accident). Riskind's seizure was triggered by an inoperable brain tumor, a condition for which he had been receiving treatment from the defendant Dr. Fred H. Hochberg since its diagnosis in September, 2000. As a result of the accident, Medina sustained serious injuries including a broken right arm that required multiple surgeries. Riskind died in June, 2002, as a result of his brain tumor.

Medina instituted this action in January, 2004, against Francine Pillemer, Riskind's wife, as executrix of his estate.1 In March, 2005, Medina moved to amend his complaint in order to assert a negligence claim against Hochberg, alleging that he breached a duty owed to Medina to control Riskind's behavior arising from a special relationship between Hochberg and Riskind or, alternatively, that he breached a duty owed to Medina by failing to warn Riskind not to drive.2 A Superior Court judge concluded that Medina's amended complaint stated a viable negligence claim against Hochberg and allowed the motion to amend. In September, 2009, Hochberg moved for summary judgment arguing that, as a matter of law, he owed Medina neither a duty to control Riskind nor a duty to warn Riskind against driving. A different Superior Court judge (motion judge) granted Hochberg's summary judgment motion. Thereafter, Medina appealed, and we granted his application for direct appellate review.3

We conclude, as we did most recently in Leavitt v. Brockton Hosp., Inc., 454 Mass. 37, 42 (2009) (Leavitt), that a medical professional (other than a mental health professional) owes no duty to a third person arising from any claimed special relationship between the medical professional and a patient. We also conclude that Hochberg did not owe a duty of care to Medina under ordinary negligence principles, and decline to extend the narrow rule announced in Coombes v. Florio, 450 Mass. 182 (2007) (Coombes), that a physician owes a limited duty to third parties, foreseeably at risk from a patient's decision to operate a motor vehicle, to warn the patient of the known side effects of medications the physician has prescribed that might impair the patient's ability as a motorist. Accordingly, we affirm the Superior Court judge's allowance of Hochberg's motion for summary judgment.

1. Background. In September, 2000, Riskind had a seizure while rowing on the Charles River that, it was later discovered, was caused by an inoperable, malignant brain tumor. Beginning in November, 2000, and continuing through the date of the accident, Hochberg, a physician practicing at Massachusetts General Hospital, was Riskind's treating neurologist. Riskind saw Hochberg at least once a month between November, 2000, and April, 2002, during which time Hochberg closely monitored Riskind's condition. Hochberg had extensive discussions with Riskind about his tumor, his treatment options, and his progress. He explained that under Massachusetts law, Riskind was not permitted to drive for a period of six months from the date of his September, 2000, grand mal seizure.4 Riskind followed Hochberg's instructions, and did not resume driving until March, 2001.5

Following his diagnosis in the late fall of 2000, Riskind suffered from multiple "sensory seizures," which caused him to feel localized numbness or tingling in his upper extremities. However, unlike a grand mal seizure,6 these sensory seizures did not interrupt normal motor activity, cause difficulty speaking, or produce confusion. Hochberg prescribed medication to control the sensory seizures, which initially helped. Riskind developed a second tumor in the summer of 2001 that increased his sensory seizures, resulting in speech difficulty, an inability to explain his needs to others, headaches, and infacility. Hochberg decided to adjust Riskind's medications, and by October, 2001, Riskind's seizures were occurring less than once per day, and were localized in his right hand. As a result, Riskind's over-all condition improved, and Hochberg noted in a report he sent to Riskind on October 17, 2001, "Most importantly your speech is ... better.... You are now able to converse with individuals, drive a car, [and] speak to patients over the telephone but have not returned to active work."7 By the end of November, 2001, other than arm stiffness, shortness of breath, and continued speech difficulty, Riskind was having no other "intercurrent problems" and was seizure free. As of December 3, 2001, the date of his last visit with Hochberg prior to the accident, Riskind remained seizure free.

Six days later, on December 10, 2001, Riskind experienced a grand mal seizure while driving home from work, causing the accident and the injuries to Medina at issue here. During the six months following the accident, Riskind's health steadily deteriorated, and he ultimately died on June 28, 2002.

Discussion. 1. Standard of review. We review a grant of summary judgment de novo. Miller v. Cotter, 448 Mass. 671, 676 (2007). Summary judgment is appropriate when, "viewing the evidence in the light most favorable to the nonmoving party, all material facts have been established and the moving party is entitled to a judgment as a matter of law." Augat, Inc. v. Liberty Mut. Ins. Co., 410 Mass. 117, 120 (1991).

2. Duty of care owed by physicians to nonpatients. "Whether a defendant has a duty of care to the plaintiff in the circumstances is a question of law for the court, to be determined by reference to existing social values and customs and appropriate social policy." O'Sullivan v. Shaw, 431 Mass. 201, 203 (2000), citing Davis v. Westwood Group, 420 Mass. 739, 743 (1995).8 A physician owes a legal duty to a patient to provide medical treatment that meets the standard of care of the average qualified physician in his or her area of specialty. Brune v. Belinkoff, 354 Mass. 102, 109 (1968). In some instances, this may require a physician to warn a patient of the risks associated with his or her treatment. See Vasa v. Compass Med., P.C., 456 Mass. 175, 177-178 (2010) (warning patients of symptoms reasonably likely to be experienced as result of medical treatment that will render unsafe everyday activities such as driving is treatment-related medical activity within medical malpractice tribunal statute). In other instances, the standard of care may require a physician to inform a patient of the side effects of prescribed medications if he or she deems such information to be necessary and relevant to the patient making an informed decision. Cottam v. CVS Pharmacy, 436 Mass. 316, 321 (2002) (Cottam). In such cases, the duty is owed by the physician to the patient.

In the present case, Medina argues that we should recognize a parallel duty owed by physicians to members of the public who might be injured by a patient as a consequence of the underlying medical condition that the physician is treating. Medina contends that such a duty arises out of either a purported special relationship between a physician and a patient or ordinary negligence principles. We consider each in turn, and conclude that neither provides a convincing ground to impose such a duty or liability on a physician.

a. Special relationship. We squarely addressed this issue in Leavitt, supra at 39-44. There, a police officer sued a hospital and two nurses for injuries he sustained when his police cruiser was hit by another automobile as he was responding to an accident involving a sedated patient who had been discharged from the hospital and had been struck by a motor vehicle while walking on the side of the road. Id. at 38-39. In our analysis, we noted that "[a]bsent a special relationship with a person posing a risk, there is no duty to control another person's conduct to prevent that person from causing harm to a third party." Id. at 40-41, citing Restatement (Second) of Torts § 315(a) (1965).9 Because we determined that medical providers do not have a "special relationship" with their patients that would give rise to such a duty, we rejected the police officer's claim. Leavitt, supra at 42. We also noted that in Coombes, supra at 187, 202, 207 n.3, a "majority of the justices of this court rejected the claim that a duty to third parties to warn a patient derived from a special relationship between the physician and patient." Leavitt, supra at 42 n.12. We decline to depart from these precedents.10

b. Ordinary negligence. We turn to Medina's contention that based on our decision in Coombes, supra, we should expand a physician's potential liability by creating a new duty owed by the physician to nonpatients to warn his or her patient of the dangers of driving in light of the patient's underlying medical condition.

In the Coombes case, the court considered a similar question, namely "whether a physician owes a duty of care to someone other than his patient for harm caused by his failure to warn the patient of the effects of his treatment of that patient." Id. at 183 (Ireland, J., concurring). In that case, the decedent died of injuries he sustained when he was struck by an automobile driven by a man who allegedly lost control of his vehicle due to the side effects of medication that the defendant physician had prescribed. Id. at 183-184.

A majority of the court concluded that a physician may be liable to a third party for failing to warn his or her patient of the known side effects of medication prescribed by the physician that might affect the patient's ability to drive a motor vehicle.11 See id. at 190, 194 (Ireland, J., concurring); id. at 196 (Greaney, J., concurring in part and dissenting in part). The court's holding represented the common ground between Justice Ireland's conclusion that "a physician owes a duty of reasonable care to everyone foreseeably put at risk by his failure to warn of the side effects of his treatment of a patient" (emphasis added), id. at 190 (Ireland, J., concurring), and Justice Greaney's narrower stance that "a physician who has knowledge of a danger that may be posed to others from a patient's decision to operate a motor vehicle while under the influence of prescribed medication [and who] does not warn the patient of the risks involved... may be held liable for injuries to others caused by the failure to warn" (emphasis added). Id. at 196 (Greaney, J., concurring in part and dissenting in part).

The rationale of Justice Greaney's narrow explication of the duty was based on the principle that "[t]o a physician, it is the patient ... who must always come first," id. at 197 (Greaney, J., concurring in part and dissenting in part), and on the concern that a broader duty to warn of side effects of treatment would place a physician in the untenable position of mediating between his or her loyalty to a patient, on the one hand, and avoiding liability to nonpatients, on the other. Id. ("A physician should not, in ordinary circumstance, be held legally responsible for the safety of others on the highway, or elsewhere, based on medical treatment afforded a patient"). Even so, he reasoned that "[e]xtending the scope of liability for the benefit of third parties foreseeably put at risk by an uninformed patient's decision to drive alters neither the physician's medical decision to prescribe medication nor the physician's legal duty under the Cottam decision to warn the patient about adverse side effects." Id. at 198. Thus, in his view, such a duty would not intrude on the physician-patient relationship. Id.

The duty Medina entreats us to establish in this case is significantly broader than the duty we adopted in Coombes.12 It would impose on physicians an affirmative duty owed to nonpatients to warn patients of the risks of driving due to any underlying medical condition. We conclude this is an unwarranted and ill-advised expansion of liability for several reasons.

First, the difference between the duty proposed by Medina and the more limited one adopted in Coombes is not merely a matter of degree; it is a matter of kind.13 The limited duty recognized in Coombes is premised on a physician's affirmative decision to prescribe a drug with known, quantifiable side effects. Id. at 194 (Ireland, J., concurring). In prescribing the medication, a physician has created the possibility that the patient might decide to operate a motor vehicle while taking it, experience a known side effect, and cause bodily injury to a nonpatient. Thus, a physician's decision to prescribe medication to his patient creates or increases the risk of harm to the general public.

The risk that Riskind posed, however, cannot be traced back to any affirmative treatment let alone medication prescribed by Hochberg. Riskind's seizure activity was a symptom of a naturally-occurring brain tumor. Taken to its logical end, Medina's proposed duty would require warning patients about the dangers associated with driving based on any number of preexisting health conditions, none of which stems from the physician's affirmative treatment of the patient. Thus, we agree with the motion judge's conclusion that the "simple act of accepting Riskind as a patient, with his preexisting medical condition, cannot be the basis for imposing a duty on Dr. Hochberg to an unlimited number of people with whom he has no relationship, with attendant liability for harm caused by the effects of the medical condition ... not caused by any act of Dr. Hochberg." See Jarmie v. Troncale, 306 Conn. 578, 607, 618-619 (2012) (Jarmie) (no duty to nonpatients to warn patient of risks of driving due to underlying condition).

In addition to this important legal distinction, a policy-based, cost-benefit analysis, weighing the benefits of such a duty against the countervailing costs of intruding into the highly personal, confidential physician-patient relationship, also counsels against imposing such an expansive duty. On the one hand, as Medina asserts, the putative benefit of imposing such a duty would be an increase in public safety. On the other hand, such a duty would threaten the autonomous nature of the physician-patient relationship by causing a physician to "become less concerned about the particular requirements of any given patient, and more concerned with protecting himself or herself from lawsuits by the potentially vast number of persons who will interact with and may fall victim to that patient's conduct outside of the treatment setting." Coombes, supra at 211 (Cordy, J., dissenting). See Jarmie, supra at 607 (such duty would interfere with physician's duty of loyalty to patient). This in turn would affect the "substance and extent of the doctor's advice and judgment" regarding which underlying conditions require warnings and which do not. Coombes, supra (Cordy, J., dissenting). See id. at 203 (Marshall, C.J., dissenting). It would also invite significantly increased litigation by third parties against doctors, resulting in an attendant increase in expenses at a time when our health care system is already overwhelmed with collateral costs. See Jarmie, supra at 614. Finally, the duty would also "threaten the confidentiality inherent in the doctor-patient relationship" by potentially requiring a physician to reveal private medical records concerning a patient's underlying medical condition in order to comply with inevitable discovery requests. Coombes, supra at 213 (Cordy, J., dissenting). See Jarmie, supra at 607.

Because we conclude that the duty proposed by Medina represents an unwarranted expansion of Coombes, we decline his invitation to create a new duty based on ordinary negligence principles.

Conclusion. In sum, we reject the dual bases presented by Medina for establishing a new duty, and conclude that a physician does not owe a duty to nonpatients to warn his or her patients of the dangers of driving posed by a patient's underlying medical condition. Because Medina cannot show that Hochberg owed him a cognizable legal duty, Hochberg is entitled to summary judgment as a matter of law. Accordingly, the motion judge's grant of summary judgment in favor of the defendant is affirmed.

So ordered.